Breeding

The Northern Flicker is characterized by a "fast" life-history with larger clutches than most other woodpeckers and a relatively short lifespan. Most individuals appear to attempt breeding as yearlings and every year thereafter. Both sexes are involved at all stages of nesting, but the species has partially-reversed sex roles, with the male contributing more parental care than the female.

Pair Formation

Few observations; more studies are needed with banded birds. In Iowa and Kansas, courtship starts about mid-April with pair formation by the end of April or early May (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close , 210 Johnson, C. A. (1934). The chronicle of a flicker's courtship. Auk 51:477–481. Close ). At Riske Creek in central British Columbia, territory establishment and pair formation probably happen concurrently and shortly after arrival on the breeding site after migration (i.e., mid-April to early May; KLW). Divorced birds initiated laying later than birds pairing with the same partner from the previous year, suggesting that renewing a former pair-bond took less time than establishing a new pair (190 Wiebe, K. L. (2022). Neither sex appears to benefit from divorce within migratory Northern Flickers consistent with accidental loss and bet-hedging. Ornithology 139:1–11. Close ). Phenology for subspecies in Cuba, Grand Cayman Island, and Guatemala is poorly known. In Guatemala, flickers seemed to pair by early February with egg-laying probably starting about 1 March (211 Dickey, D. R., and A. J. van Rossem (1938). The birds of El Salvador. Field Museum of Natural History Zoological Series, Chicago, IL, USA. Close ). On Grand Cayman Island, breeding occurred between January and August with peaks from March to July; it was claimed that pair bonds were retained most of the year (212 Bradley, P. E. (2000). The Birds of the Cayman Islands: An Annotated Check-list. BOU Check-list 19. British Ornithologists’ Union, Tring, UK. Close ), although without color-banded individuals, the evidence for this is not clear.

Nest-Building

Figure 1. At Pimsi Bay, Ontario, mean starting date for nest-cavity excavation was 9 May (range 29 April–15 May, n = 10; 146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ). For southeastern Wisconsin, mean starting date was 17 April (range 2 April–23 May, n = 13; 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Duration of excavation period was 12.1 d for Ontario (range 5–19, n = 7; 146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ) and 15.2 d for Wisconsin (range 11–20, n = 13; 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ).

First Brood/Only Brood

There are no confirmed records of second broods and this would be hard to determine without color-banded individuals. However, the relatively long breeding cycle of the Northern Flicker means that only one brood can probably be raised in most of the geographic range (213 Gow, E. A., and K. L. Wiebe (2012). An unusually synchronous double brooding attempt by a Northern Flicker pair. Wilson Journal of Ornithology 124:389–392. Close ), but a pair may renest if their first clutch is destroyed. In central British Columbia, the annual mean laying date in the population was negatively correlated with temperature on the study area from 20 April–4 May (i.e., during the period shortly before egg laying), becoming 1.15 days earlier for every degree warmer during that spring period (152 Wiebe, K. L., and H. Gerstmar (2010). Influence of spring temperatures and individual traits on reproductive timing and success in a migratory woodpecker. Auk 127:917–925. Close ). Because there is little activity of ants on the ground surface at ambient temperatures < 5°C (159 Wiebe, K. L., and E. A. Gow (2013). Choice of foraging habitat by northern flickers reflects changes in availability of their ant prey linked to ambient temperature. Ecoscience 20:122–130. Close ) and female flickers probably depend on a sufficient abundance of ants to increase body condition and lay eggs, it makes sense that the timing of egg laying is correlated with ambient temperatures and probably latitude. During 12 years at Riske Creek (ca. 52°N), the average initiation date for clutches (n = 1,182) was 14 May (range 26 April–13 June; 152 Wiebe, K. L., and H. Gerstmar (2010). Influence of spring temperatures and individual traits on reproductive timing and success in a migratory woodpecker. Auk 127:917–925. Close ). In Washington state (46°N), the mean laying date was 17 May (range 1 May–13 June, n = 47, 214 Kozma, J. M., and A. J. Kroll (2012). Woodpecker nest survival in burned and unburned managed ponderosa pine forests of the northwestern United States. Condor 114:173–184. Close ). In Nebraska (ca. 41°N) from 1982–1994, modal date in different years for first egg laid was 9–18 May (range 1 May–1 June, n = 30; WSM). In Wyoming (42°N) and New Mexico (34°N), modal dates were 7–12 May and 1–6 May, respectively (WSM). The latest initiation date of a replacement clutch at Riske Creek was 2 July (KLW).

Selection Process

Not well understood. Some have reported that the female chooses the nest site (172 Kilham, L. (1959). Early reproductive behavior of flickers. Wilson Bulletin 71:323–336. Close , 133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close ), while others concluded that the male did (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close , 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Ritualized tapping (see Nonvocal Sounds) may communicate information between pair members regarding acceptability of a nest site. Individuals are usually philopatric to home ranges, but not necessarily to nest trees (137 Fisher, R. J., and K. L. Wiebe (2006). Breeding dispersal of Northern Flickers Colaptes auratus in relation to natural nest predation and experimentally increased perception of predation risk. Ibis 148(4):772–781. Close , 190 Wiebe, K. L. (2022). Neither sex appears to benefit from divorce within migratory Northern Flickers consistent with accidental loss and bet-hedging. Ornithology 139:1–11. Close ). Nest cavities are frequently reused (215 Wiebe, K. L., W. D. Koenig, and K. Martin (2007). Costs and benefits of nest reuse versus excavation in cavity-nesting birds. Annales Zoologici Fennici 44:209–217. Close ). Indeed, based on 1,843 first nests over 18 years of study at Riske Creek, an average of only 23% were freshly excavated that year; the majority were placed in existing (reused) holes (216 Wiebe, K. L. (2017). Northern flickers only work when they have to: how individual traits, population size and landscape disturbances affect excavation rates of an ecosystem engineer. Journal of Avian Biology 48:431–438. Close ). The frequency of freshly excavated nests declined seasonally, suggesting that flickers are more likely to select existing holes when faced with time constraints for breeding (216 Wiebe, K. L. (2017). Northern flickers only work when they have to: how individual traits, population size and landscape disturbances affect excavation rates of an ecosystem engineer. Journal of Avian Biology 48:431–438. Close ).

Site Characteristics

Usually excavates nest cavities in dead or diseased tree trunks and large branches. Wood hardness was the primary factor determining which trees were selected on home ranges and where on the tree the nest was excavated (217 Lorenz, T. J., K. T. Vierling, T. R. Johnson, and P. C. Fischer (2015). The role of wood hardness in limiting nest site selection in avian cavity excavators. Ecological Applications 25:1016–1033. Close ) but the Northern Flicker can use a wide breadth of decay classes of trees (218 Blanc, L. A., and K. Martin (2012). Identifying suitable woodpecker nest trees using decay selection profiles in trembling aspen. Forest Ecology and Management 286:192–202. Close ). It uses a diversity of tree species but prefers trembling aspen (Populus tremuloides) over more abundant conifer species (96% of nests at Riske Creek were in aspens; 123 Wiebe, K. L. (2001). Microclimate of tree cavity nests: Is it important for reproductive success in northern flickers? Auk 118(2):412–421. Close , 5 Martin, K., K. E. H. Aitken, and K. L. Wiebe (2004). Nest sites and nest webs for cavity-nesting communities in interior British Columbia, Canada: Nest characteristics and niche partitioning. Condor 106(1):5–19. Close ). Probably the typical heart rot in mature aspens makes them easier to excavate (219 Harestad, A. S., and D. G. Keisker (1989). Nest tree use by primary cavity nesting birds in south central British Columbia. Canadian Journal of Zoology 67:1067–1073. Close ). In El Salvador, the Guatemalan Flicker (subspecies ) usually nests in tall dead pine trees, sometimes in half-rotten oak stubs (211 Dickey, D. R., and A. J. van Rossem (1938). The birds of El Salvador. Field Museum of Natural History Zoological Series, Chicago, IL, USA. Close ). In Miami, Florida, 58% of 40 nests were placed in dead palm trees (220 Diamond, J. M., M. S. Ross, H. Liu, and J. T. Heinen (2020). Palm snags are a critical nesting resource for woodpeckers in an urbanized tropical region. Urban Ecosystems 23:67–78. Close ). In deserts it may nest in saguaro cacti (Carnegiea gigantea) and may usurp or enlarge cavities in cacti originally made by Gila Woodpecker (Melanerpes uropygialis) (221 Kerpez, T. A., and N. S. Smith (1990). Nest-site selection and nest-cavity characteristics of Gila Woodpeckers and Northern Flickers. Condor 92:193–198. Close ). Rarely may nest in earthen burrows; e.g., used nest burrows of Belted Kingfisher (Megaceryle alcyon) or Bank Swallow (Riparia riparia) (222 Dennis, J. V. (1969). The Yellow-shafted Flicker (Colaptes auratus) on Nantucket Island, Massachusetts. Bird-Banding 40:290–308. Close ). There are a handful of reports of Northern Flickers nesting directly on the ground, a review of cases is in (223 Reese, J. G., and D. Bridge (2015). Rare occurrences of ground-nesting in the Northern Flicker. Maryland Birdlife 64:14–22. Close ), but no such nest has been successful.

In Wisconsin, 92% of nest cavities were in dead trees (193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ); in Ontario 76% (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ), similar to the 74% reported by (224 Gutzwiller, K. J., and S. H. Anderson (1987). Multiscale associations between cavity-nesting birds and features of Wyoming streamside woodlands. Condor 89:534–548. Close ). In British Columbia 53% (n = 160) were in dead trees and most other nests in diseased trees (123 Wiebe, K. L. (2001). Microclimate of tree cavity nests: Is it important for reproductive success in northern flickers? Auk 118(2):412–421. Close ). In Sierra Nevada Mountains., 78% of 68 nests were in snags, 20% in dead portions of live trees, 2% in live portions of live trees (118 Raphael, M. G., and M. White (1984). Use of snags by cavity-nesting birds in the Sierra Nevada. Wildlife Monographs 86:1–66. Close ). On Nantucket Island, Massachusetts, 87.5% in trees, 12.5% in other structures (mostly buildings); of nests in trees, 62% were in dead trees, 4% in dead branches of live trees (222 Dennis, J. V. (1969). The Yellow-shafted Flicker (Colaptes auratus) on Nantucket Island, Massachusetts. Bird-Banding 40:290–308. Close ). In Ohio, 63.6% of nests were in dead trees, 36.4% were in live trees, and 79.5% (total) were in dead limbs (n = 44; 225 Ingold, D. (1994). Nest-site characteristics of Red-bellied and Red-headed Woodpeckers and Northern Flickers in east-central Ohio. Ohio Journal of Science 94:2–7. Close ). Along the South Platte River (Colorado), only 27% of nest cavities were in dead trees, although a total of 61% were in dead substrate (119 Sedgwick, J. A., and F. L. Knopf (1990). Habitat relationships and nest site characteristics of cavity-nesting birds in cottonwood floodplains. Journal of Wildlife Management 54:112–124. Close ). When Northern Flickers excavate in live trees, they often use knotholes (58% of cavities) formed by broken limbs as starting points presumably because these are starting points for decay (119 Sedgwick, J. A., and F. L. Knopf (1990). Habitat relationships and nest site characteristics of cavity-nesting birds in cottonwood floodplains. Journal of Wildlife Management 54:112–124. Close ).

Nest height above ground is variable. Average nest cavity heights: Wisconsin 5.7 m (range 3–10, n = 16; 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ); Ontario 7.0 m (range 2.4–13.7, n = 25; 146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ); Iowa 8.1 m ± 3.2 SD (n = 31; 226 Stauffer, D. F., and L. B. Best. (1982). Nest-site selection by cavity-nesting birds of riparian habitats in Iowa. Wilson Bulletin 94:329–337. Close ); Ohio 8.4 m ± 0.65 SD (n = 44; 225 Ingold, D. (1994). Nest-site characteristics of Red-bellied and Red-headed Woodpeckers and Northern Flickers in east-central Ohio. Ohio Journal of Science 94:2–7. Close ); and Wyoming 7.3 m ± 0.6 SD (n = 28; 224 Gutzwiller, K. J., and S. H. Anderson (1987). Multiscale associations between cavity-nesting birds and features of Wyoming streamside woodlands. Condor 89:534–548. Close ). Significantly lower average heights on Nantucket Island, Massachusetts, where trees are scrubbier: 1.3 m (range 0.0–5.18, n = 169; 222 Dennis, J. V. (1969). The Yellow-shafted Flicker (Colaptes auratus) on Nantucket Island, Massachusetts. Bird-Banding 40:290–308. Close ), but greater heights in tall Douglas-fir (Pseudotsuga menziesii) in western Oregon: 11.4 m (range 3.0–26.8, n = 8; 117 Mannan, R. W., E. C. Meslow, and H. M. Wight (1980). Use of snags by birds in Douglas-fir forests, western Oregon. Journal of Wildlife Management 44:787–797. Close ).

May use nestboxes especially where natural cavities are scarce. However, only one pair was ever recorded in the 50 nestboxes placed at Riske Creek over the duration of the study. Natural holes are abundant at Riske Creek so such cavities were clearly preferred over boxes.

Construction Process

Both sexes participate in cavity excavation, but the male plays dominant role. During cavity excavation in Ontario, either male or female excavated 40% of observation time (795 mins, 10 nests): male 68% of excavation time, female 32% (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ). In Wisconsin, males performed 88% of excavation at 12 nests (193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). In New Hampshire, the male of a pair observed did 81% of the excavating (133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close ). Female participation appears to increase toward the end of excavation (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close , 133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close , 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). The nest cavity is excavated by “chiseling” away small chips of wood with bill; the bird starts by clinging to the trunk, using its tail as a prop, then perching on the lower lip of the nest opening as it works its way into the interior. Periods of chiseling are interspersed with shorter periods of tossing chips from the cavity opening; chips are also carried away in the bill.

No detailed data on diurnal distribution of excavation activity, but nest excavation observed throughout daylight hours. Length of time to build a nest is highly variable, depending on whether it is a new excavation, hardness of wood, and intensity of excavation effort. Mean excavation time in Ontario was 12.1 d (range 5–19, n = 10; 146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ); in Wisconsin 15.2 d (range 11–20, n = 15; 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Lawrence (146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close ) reported short and irregular periods for 16 observed periods of excavation; e.g., mean minimum duration: male 13.3 (range 1–50), female 19.7 (range 3–40). Kilham (133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close ) described two nest excavations, one in which the male did 81% of excavation and worked 60–80 min at a stretch, and the other in which the female did the most excavation and worked for periods up to 85 min.

Structure and Composition

The cavity curves quickly downward beyond the entrance, and the diameter rapidly expands beyond the entry hole; the front wall is typically < 2.5 cm thick. The cavity is usually cylindrical with a slightly concave floor. The entrance is typically just large enough to accommodate the entry and exit of adults; the interior is large enough for adults to turn around. Eggs are laid directly on a bed of wood chips.

Dimensions

Average horizontal diameter of entrance holes reported from various locales: 8.33 cm (132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close ); 7.3 cm ± 0.21 SE in Ohio (n = 32; 225 Ingold, D. (1994). Nest-site characteristics of Red-bellied and Red-headed Woodpeckers and Northern Flickers in east-central Ohio. Ohio Journal of Science 94:2–7. Close ); 6.58 cm ± 0.21 SE in Wyoming (n = 28; 224 Gutzwiller, K. J., and S. H. Anderson (1987). Multiscale associations between cavity-nesting birds and features of Wyoming streamside woodlands. Condor 89:534–548. Close ); 6.9 cm ± 0.5 SE in central British Columbia (n = 14; 227 Peterson, B., and G. Gauthier (1985). Nest site use by cavity-nesting birds of the Cariboo Parkland, British Columbia. Wilson Bulletin 97:319–331. Close ); and 6.45 cm ± 0.03 SE at Riske Creek in central British Columbia (n = 596; KLW). Vertical diameters are often slightly longer. Interior diameter of the cavity near the bottom floor: 19.48 cm (132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close ) and 14.6 cm ± 0.11 SE (n = 559; KLW). Vertical depth from entrance to floor: 40.11 cm (range 15.24–91.44; 132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close ), 33.7 cm ± 2.5 SE (227 Peterson, B., and G. Gauthier (1985). Nest site use by cavity-nesting birds of the Cariboo Parkland, British Columbia. Wilson Bulletin 97:319–331. Close ), and 39.0 cm ± 0.53 SE (n = 584; KLW). Breadth (inside edge of entrance to back wall): 14.9 cm ± 0.6 SE, and floor area 158 cm² ± 12 SE (227 Peterson, B., and G. Gauthier (1985). Nest site use by cavity-nesting birds of the Cariboo Parkland, British Columbia. Wilson Bulletin 97:319–331. Close ). Wiebe and Swift (228 Wiebe, K. L., and T. L. Swift (2001). Clutch size relative to tree cavity size in Northern Flickers. Journal of Avian Biology 32(2):167–173. Close ) reported a mean floor area of 166 cm² ± 6.4 SE, but 3 extraordinarily large cavities in hollow trees had floor areas > 400 cm² (see Table 1 in 123 Wiebe, K. L. (2001). Microclimate of tree cavity nests: Is it important for reproductive success in northern flickers? Auk 118(2):412–421. Close ).

Nest tree and limb size variable. Diameter of tree at breast height: 46.9 cm ± 2.7 SE in Ohio (n = 42; 225 Ingold, D. (1994). Nest-site characteristics of Red-bellied and Red-headed Woodpeckers and Northern Flickers in east-central Ohio. Ohio Journal of Science 94:2–7. Close ); 30.0 cm ± 2.0 SE in British Columbia (n = 14; 227 Peterson, B., and G. Gauthier (1985). Nest site use by cavity-nesting birds of the Cariboo Parkland, British Columbia. Wilson Bulletin 97:319–331. Close ); 33.9 cm ± 0.81 SE in British Columbia (n = 160; 123 Wiebe, K. L. (2001). Microclimate of tree cavity nests: Is it important for reproductive success in northern flickers? Auk 118(2):412–421. Close ); 46.3 cm ± 4.1 SE in Wyoming (n = 28; 224 Gutzwiller, K. J., and S. H. Anderson (1987). Multiscale associations between cavity-nesting birds and features of Wyoming streamside woodlands. Condor 89:534–548. Close ); and 31.9 cm ± 2.4 in British Columbia (n = 17; 219 Harestad, A. S., and D. G. Keisker (1989). Nest tree use by primary cavity nesting birds in south central British Columbia. Canadian Journal of Zoology 67:1067–1073. Close ). Tree diameter at nest height: 34.5 cm ± 10.6 SD in Iowa (n = 31; 226 Stauffer, D. F., and L. B. Best. (1982). Nest-site selection by cavity-nesting birds of riparian habitats in Iowa. Wilson Bulletin 94:329–337. Close ); 27.1 cm ± 2.0 SE in Wyoming (n = 28; 224 Gutzwiller, K. J., and S. H. Anderson (1987). Multiscale associations between cavity-nesting birds and features of Wyoming streamside woodlands. Condor 89:534–548. Close ); and 31.3 cm ± 0.29 SE in British Columbia (n = 133; 123 Wiebe, K. L. (2001). Microclimate of tree cavity nests: Is it important for reproductive success in northern flickers? Auk 118(2):412–421. Close ).

Microclimate

Dataloggers placed in cavities in central British Columbia just after nestlings fledged (123 Wiebe, K. L. (2001). Microclimate of tree cavity nests: Is it important for reproductive success in northern flickers? Auk 118(2):412–421. Close ) showed that temperature fluctuations in cavities were less extreme than in the environment and reached a low of about 5°C between 0600–0700 h and as high as 32°C around 1750 h in July. Diel temperature variation was greatest in small diameter trees and in highly decayed trees. South-facing cavities reached the highest daytime temperatures, and entrances were oriented non-randomly towards the south, suggesting cavities were excavated to gain thermal advantages. The interior temperature of eight occupied cavities in Montana was fairly stable relative to ambient temperature and did not vary more than 5°C from the mean temperature of 20.4°C (229 Howe, S., D. L. Kilgore, and C. Colby (1987). Respiratory gas concentrations and temperature within the nest cavities of the Northern Flicker (Colaptes auratus). Canadian Journal of Zoology 65:1541–1547. Close ).

Other studies have also found that nest hole orientation is significantly skewed toward the East, Southeast, and South (n = 160 nests; data pooled from 146 Lawrence, L. D. (1966). A comparative life-history study of four species of woodpeckers. Ornithological Monographs 5. Close , 222 Dennis, J. V. (1969). The Yellow-shafted Flicker (Colaptes auratus) on Nantucket Island, Massachusetts. Bird-Banding 40:290–308. Close , and 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). However, there was no significant bias reported for studies in Ohio (n = 44; 225 Ingold, D. (1994). Nest-site characteristics of Red-bellied and Red-headed Woodpeckers and Northern Flickers in east-central Ohio. Ohio Journal of Science 94:2–7. Close ) and Iowa (n = 31; 226 Stauffer, D. F., and L. B. Best. (1982). Nest-site selection by cavity-nesting birds of riparian habitats in Iowa. Wilson Bulletin 94:329–337. Close ).

Maintenance or Reuse of Nests

Northern Flicker tends to use existing nest cavities more frequently than most other woodpeckers but reuse is quite variable among populations (230 Wiebe, K. L., W. D. Koenig, and K. Martin (2006). Evolution of clutch size in cavity-excavating birds: The nest site limitation hypothesis revisited. American Naturalist 167(3):343–353. Close ). Before reuse, the Northern Flicker lays down a fresh bed of woodchips on the bottom by further excavating some of the interior wall. In Wisconsin, reuse was in 2 of 16 nests (13%; 193 Burkett, E. W. (1989). Differential roles of sexes in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ); Ohio, 20 of 44 (45.5%; 225 Ingold, D. (1994). Nest-site characteristics of Red-bellied and Red-headed Woodpeckers and Northern Flickers in east-central Ohio. Ohio Journal of Science 94:2–7. Close ); British Columbia, 63% of 739 (230 Wiebe, K. L., W. D. Koenig, and K. Martin (2006). Evolution of clutch size in cavity-excavating birds: The nest site limitation hypothesis revisited. American Naturalist 167(3):343–353. Close ). On the Great Plains (Nebraska, Colorado, Wyoming, New Mexico), of 14 individuals banded as adults and recovered in a subsequent breeding season, 3 reused the same nest cavity where they were captured for banding (WSM). Northern Flicker sometimes complete excavation of a nest cavity partially excavated in a previous year or it may renovate or enlarge cavities previously excavated by other species of woodpeckers (231 Murphy, M. T. (1981). Yellow-bellied Sapsucker displaced by Common Flicker. Loon 53(3):174. Close ). Propensity to excavate a new nest increased after wildfire destroyed 40% of the existing cavities at Riske Creek, British Columbia; fewer existing holes were available for reuse, and reused nests were more often in large, living trees because many of the dry, dead snags burned (232 Wiebe, K. L. (2014). Responses of cavity nesting birds to fire: testing a general model with data from the northern flicker. Ecology 95:2537–2547. Close ).

Shape

Ovate, varying to short-ovate, elliptical-ovate, nearly oval, and rarely somewhat pointed (9 Bent, A. C. (1939). Life histories of North American woodpeckers. United States National Museum Bulletin 174, Smithsonian Institution, Washington, DC, USA. Close ).

Size

Given (in centimeters) as mean length × breadth (min, max), sample size. For the southern United States: 2.79 × 2.16 (2.29 × 1.91, 3.15 × 2.34), n = 133; for New England, New York, Ontario, and Pennsylvania: 2.77 × 2.17, n = 233; for Midwest (Ohio, Kentucky, Wisconsin, Kansas, Nebraska, Iowa, and Minnesota): 2.76 × 2.17 (2.36 × 1.65, 3.58 × 2.36), n =126 (132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close ). In western North America: 2.82 × 2.19 (2.54 × 2.08, 3.56 × 2.03), n = 57; northwestern United States (northern California–Alaska): 2.93 × 2.24 (2.64 × 2.08, 3.20 × 2.34), n = 47 (9 Bent, A. C. (1939). Life histories of North American woodpeckers. United States National Museum Bulletin 174, Smithsonian Institution, Washington, DC, USA. Close ). In central British Columbia, egg length is 2.81 cm ± 1.6 SD, breadth 2.18 cm ± 1.1 SD, n = 288 (233 Wiebe, K. L. (2006). Egg composition in Northern Flickers. Condor 108(4):977–980. Close ); range (i.e., minimum–maximum measures) for length 1.86–3.65 cm, breadth 1.60–3.31 (KLW).

Abnormally small "runt" eggs are found in < 5% of clutches, typically as the first-laid egg of a sequence (KLW).

Mass and Composition

Based on 17 eggs from 3 clutches: 5.4 g ± 0.23 SD (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ). From 27 eggs from 27 different clutches: 7.01 g ± 0.61 SD (233 Wiebe, K. L. (2006). Egg composition in Northern Flickers. Condor 108(4):977–980. Close ). Of the wet egg weight, the proportion of yolk (16%) is among the smallest of any bird species although lipid content of the yolk (58%) is similar to that of other altricial birds (233 Wiebe, K. L. (2006). Egg composition in Northern Flickers. Condor 108(4):977–980. Close ).

Eggshell Thickness

No data. Eggshells weighed on average 0.58 g (233 Wiebe, K. L. (2006). Egg composition in Northern Flickers. Condor 108(4):977–980. Close ).

Color and Surface Texture

Shell is pure lustrous white and semi-glossy but egg appears pinkish up to about the 5th day of incubation because the dark orange yolk shines through the shell before the embryonic membranes are formed (KLW).

Clutch Size

Varies locally, latitudinally, and seasonally (see Measures of Breeding Activity). A pooled estimate based on clutches recorded from a range of latitudes in the United States was 6.5 ± 1.4 SD (range 3–12, n = 411; 234 Moore, W. S., and W. D. Koenig (1986). Comparative reproductive success of Yellow-shafted, Red-shafted, and hybrid flickers across a hybrid zone. Auk 103:42–51. Close ). At Riske Creek in central British Columbia (52° N), the size of first clutches was 7.99 ± 1.3 SD, n = 1579 and of second (replacement) clutches was 6.83 ± 1.1 SD, n = 266; for all clutches pooled: 7.81 ± 1.4 SD (range 2–13) n = 1,872 (KLW) . At a study site in Washington State (46.6° N), the average clutch was 7.0 (range 4–12, n = 82; 214 Kozma, J. M., and A. J. Kroll (2012). Woodpecker nest survival in burned and unburned managed ponderosa pine forests of the northwestern United States. Condor 114:173–184. Close ). At four study sites on a transect across the hybrid zone in Nebraska and Wyoming (latitude 42°N), mean clutch sizes did not differ according to phenotype and were: Sutherland, Nebraska: 7.50 ± 1.53 SD (n = 26, nearly pure Yellow-shafted Flicker); Bridgeport, Nebraska: 7.16 ± 1.37 SD (n = 32, hybrid); Morrill, Nebraska 6.97 ± 1.28 SD (n = 32, hybrid); Wheatland, Wyoming: 7.75 ± 1.48 SD (n = 16, hybrid tending toward pure Red-shafted Flicker) (234 Moore, W. S., and W. D. Koenig (1986). Comparative reproductive success of Yellow-shafted, Red-shafted, and hybrid flickers across a hybrid zone. Auk 103:42–51. Close ). Clutches larger than 13 eggs are likely the result of conspecific brood parasitism.

There is also a correlation with nest microclimate; larger clutches are laid in warmer cavities (123 Wiebe, K. L. (2001). Microclimate of tree cavity nests: Is it important for reproductive success in northern flickers? Auk 118(2):412–421. Close ), but clutch size is not related to size of cavity (228 Wiebe, K. L., and T. L. Swift (2001). Clutch size relative to tree cavity size in Northern Flickers. Journal of Avian Biology 32(2):167–173. Close ).

Egg-Laying

Appears to begin shortly after completion of the nest, but detailed data are not available. Eggs are laid at a rate of 1 per day, usually between 05:00 and 06:00 h (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ). Parental attentiveness at nest increases at onset of egg-laying, particularly by female, but male remains the most attentive. Based on 17 observation periods at 3 nests lasting 1 hour in length [in Colorado, Kansas, and New Mexico], one member of the pair was in the cavity 71% of the time during the egg-laying period (the male accounting for about 3/4 of the time in the cavity; WSM). One parent is usually in or near nest during egg-laying; pairs seem to switch nest-guarding duty as one leaves the area to forage (KLW).

Species is a well-known indefinite layer; i.e., when an egg is removed, it is replaced. Burns (132 Burns, F. L. (1900). Monograph of the flicker. Wilson Bulletin 7:1–82. Close ) and Bent (9 Bent, A. C. (1939). Life histories of North American woodpeckers. United States National Museum Bulletin 174, Smithsonian Institution, Washington, DC, USA. Close ) report numerous instances of oologists removing eggs singly and as whole clutches from Northern Flicker nests and the female replacing them. In one case, 1 egg was removed each day, and each day the female replaced the egg until a total of 71 eggs was laid (235 Phillips, C. L. (1887). Egg-laying extraordinary in Colaptes auratus. Auk 4:346. Close ). Relaying after destruction of a clutch may occur after 7 d (187 Wiebe, K. L. (2005). Asymmetric costs favor female desertion in the facultatively polyandrous Northern Flicker (Colaptes auratus): a removal experiment. Behavioral Ecology and Sociobiology 57(5):429–437. Close ).

Onset of Broodiness and Incubation in Relation to Laying

There have been no attempts to install thermometers in the nest bowl to directly measure the onset of incubation. However, the hatching span of eggs within a clutch, which typically varies from 1‒3 days (KLW) suggests incubation can begin on the ante-penultimate, penultimate, or last egg of the clutch. Because it is the male which incubates during the nighttime hours and during much of the day, presumably it is the broodiness of the male that largely determines the onset of embryonic development. Many (about 50%) of broods hatch "synchronously" within 24 hours (KLW). Based on direct observations of nests, Sherman (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ) similarly suggested incubation begins 0–2 d before last egg is laid.

Incubation Patches

Both male and female develop a single, large oval patch in the belly region (KLW).

Incubation Period

Based on Sherman's (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ) detailed observations of 5 eggs, the average time for embryo development (onset of incubation on that egg to the hatching of that egg) was 11.9 d (range 11.2–12.4). Incubation onset is variable (see above) but in Sherman's case, this meant that nestlings hatched 9–10 d after last egg was laid. The oldest nestlings in a brood began to hatch 10.9 d on average after the last egg was laid in 174 clutches in central British Columbia (KLW); if incubation typically begins on the penultimate egg, this would equate to an embryonic development time of about 12 d, consistent with Sherman's estimate. Woodpeckers have a similar total development time from incubation to fledging as other altricial birds but their incubation period relative to the nestling period is 57% shorter (236 Yom-Tov, Y. and A. Ar (1993). Incubation and fledging durations of woodpeckers. Condor 95:282–287. Close ). Yom-Tov and Ar (236 Yom-Tov, Y. and A. Ar (1993). Incubation and fledging durations of woodpeckers. Condor 95:282–287. Close ) hypothesized that hypoxic conditions in tree cavities selected for early hatching; however, measurements of oxygen in tree cavities with incubating females inside did not reveal oxygen deficits sufficient to inhibit embryo development (237 Wiebe, K. L. (2007). Hypoxia probably does not explain short incubation periods of woodpeckers. Condor 109:976–979. Close ).

Parental Behavior

Incubation is shared by the male and female and transfers between partners take about 10–20 seconds at the nest hole such that the clutch remains covered about 98% of the time (188 Wiebe, K. L. (2008). Division of labour during incubation in a bird species with reversed sex roles and facultative polyandry. Ibis 150:115–124. Close ). Except in rare cases, the male does all nighttime incubation (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close , 187 Wiebe, K. L. (2005). Asymmetric costs favor female desertion in the facultatively polyandrous Northern Flicker (Colaptes auratus): a removal experiment. Behavioral Ecology and Sociobiology 57(5):429–437. Close ). Based on continuous video monitoring during periods lasting 1–6 days at 71 nests at Riske Creek, British Columbia, the sexes switch off in 3–8 daytime bouts lasting 1.97 h ± 0.69 SD for males and 1.93 h ± 0.52 SD for females (188 Wiebe, K. L. (2008). Division of labour during incubation in a bird species with reversed sex roles and facultative polyandry. Ibis 150:115–124. Close ). The longest daytime incubation bout was 5.73 h by a male (KLW). Another estimate (sexes pooled) for daytime incubation bouts was 2.3 h based on nest observations (133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close ). Between the sunrise and sunset incubation transfers (i.e., during daylight hours), the sexes contributed approximately equally to incubation but because males incubate at night, males do 67% of the total incubation on average (n = 71 nests; 188 Wiebe, K. L. (2008). Division of labour during incubation in a bird species with reversed sex roles and facultative polyandry. Ibis 150:115–124. Close ). Polyandrous females contributed less incubation at their secondary nest than a monogamous female because they were simultaneously feeding nestlings at their primary brood (188 Wiebe, K. L. (2008). Division of labour during incubation in a bird species with reversed sex roles and facultative polyandry. Ibis 150:115–124. Close ).

Large males (in terms of structural body size) and males in poor body condition incubated less than smaller males or those with good nutrient reserves (188 Wiebe, K. L. (2008). Division of labour during incubation in a bird species with reversed sex roles and facultative polyandry. Ibis 150:115–124. Close ). Incubation pattern and the proportional contribution by each sex did not influence the incubation period or hatching success of the clutch (188 Wiebe, K. L. (2008). Division of labour during incubation in a bird species with reversed sex roles and facultative polyandry. Ibis 150:115–124. Close ).

Hardiness of Eggs against Temperature Stress; Effect of Egg Neglect

Information needed.

Preliminary Events and Vocalizations

No conspicuous changes in behavior or vocalizations associated with hatching have been noted.

Shell-Breaking and Emergence

Based on casual observation, the process is similar to many other bird species: first a pip or "star crack" appears on the wide end of an egg. Then, the crack is gradually enlarges to encircle the egg so that the shell breaks in two as the nestling emerges (KLW).

Parental Assistance and Disposal of Eggshells

No data to indicate that the parents assist in hatching the eggs. Casual observations suggest that most parents (67–75%) remove eggshells from the nest within one day of hatching, but sometimes they are left in the cavity and may "cap" other eggs, causing hatching failure (KLW). Unhatched eggs are often left on the cavity bottom.

Condition at Hatching

Hatchlings are altricial―eyes closed and lacking down or feathers. The bill, tarsus, and feet are pale pinkish-yellow to pink. There is a white fleshy fold at the jaw hinge and calcareous white "egg teeth" on the tips of both the upper and lower maxillae which help the parents to locate the mouths of nestlings in the dark cavity (238 Wiebe, K. L. (2010). A supplemental function of the avian egg tooth. Condor 112:1–7. Close ). Unlike most other birds, these egg teeth are retained throughout the nestling period, being visible even in young about to fledge (238 Wiebe, K. L. (2010). A supplemental function of the avian egg tooth. Condor 112:1–7. Close ). Hatchlings aggregate on the floor of the nest cavity, craning their heads weakly when a parent enters nest. Mean body mass at hatching 5.46 g in Iowa (n = 3; 145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ), 5.50 g in Florida (n = 10; F. Lohrer, unpublished data); approximately 6 g in British Columbia (KLW). Linear measurements not reported.

Growth and Development

See Figure 7. From Sherman (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ): mean body mass on day after hatching 11.8 g ± 3.0 SD; nestling growth roughly linear from day 2 to day 10 (77.8 g ± 8.8 SD on day 10). Growth slows from day 10 to day 18 (102.1 g ± 13.6 SD on day 15, 108.8 g ± 12.8 SD on day 18); mean weight is constant from day 19 to 25 (114.0 g ± 13.5 SD on day 25) but declines slightly just before fledging. The sexes are not distinguishable by size or mass at hatching; the logistic growth curves start to diverge for each sex around day 11, the time of maximum growth rate (see Gow et al. [239 Gow, E. A., A. B. Musgrove, and K. L. Wiebe (2013). Brood age and size influence sex-specific parental provisioning patterns in a sex-role reversed species. Journal of Ornithology 154:525–535. Close ]). Near fledging, around day 25, males weigh about 6% more than females (239 Gow, E. A., A. B. Musgrove, and K. L. Wiebe (2013). Brood age and size influence sex-specific parental provisioning patterns in a sex-role reversed species. Journal of Ornithology 154:525–535. Close ) but fledging mass for both sexes depends on brood size, peaking in a brood size of 4 and declining for larger broods. A pooled estimate of fledging mass: (male 134 g ± 0.48 SD, n = 565; female 127 g ± 0.45 SD, n = 606; KLW).

Tail and wing feathers grew at a rate of 4.09 mm/day and 3.75mm/day, respectively (239 Gow, E. A., A. B. Musgrove, and K. L. Wiebe (2013). Brood age and size influence sex-specific parental provisioning patterns in a sex-role reversed species. Journal of Ornithology 154:525–535. Close ).

The following is a summary of the external appearance of nestlings at various ages, assuming hatching day = 0. Ages are approximate (± 2 d), because the hatching asynchrony within broods means that nestlings are of slightly different ages and may develop at slightly different rates. Descriptions are based on notes and photographs taken at study sites in British Columbia (KLW) and in the central United States (WSM).

Day 0. See Condition at Hatching, above.

Days 1–16. Appear as newly hatched but larger. Day 6: feather tracts first appear in hatchlings as dark gray swellings along the posterior edge of wing (alar tract) and tail-bud (caudal tract) and along anterior and midbody regions of back (dorsal tract, anterior and saddle elements). Days 7–8: flight feathers emerge from the skin as pin feathers. Days 10–11: eyes partially opened; feather vanes begin to erupt from tips of flight-feather shafts (extending approximately 2 mm out of shafts of tail feathers); femoral tract conspicuous with white-tipped feathers emerging; white feathers of dorsal rump patch (posterior element of dorsal tract) begin to emerge; crown appears gray as feathers of capital tract begin to emerge; bill, tarsus, and feet begin to turn from pinkish to gray; skin begins to turn from pale pinkish-yellow to darker purplish pink. Days 12–16: eyes fully open, contour feathers dramatically more conspicuous; black and brown dorsal plumage spots that form barred dorsal-plumage pattern of adult conspicuous; vanes extend 5–10 mm from shafts of tail feathers; crown nearly fully feathered but with narrow, central bare strip (apterium); bill, tarsus, and toes slate-gray color as in adult.

Days 17–23. Change primarily in extent of feather growth. Day 17: vanes of emerging flight feathers begin to unfold laterally, vanes of tail feathers extend 18–21 mm from shafts. Day 19: central crown apterium nearly closed but visible as a furrow; shaft color (yellow/red) apparent in dorsal shaft surface of flight feathers; malar stripe and nuchal patch apparent. Day 23: crown apterium closed to an inconspicuous furrow; vanes of tail feathers extend approximately 25 mm. Nestlings leave nest at 24–27 d, looking like small adults with softer plumage that is duller in color.

Nestlings huddle at bottom of nest until about 11 d old, then for about 1 week, they array themselves around the circumference at bottom of cavity with their chins and throats pressed against the wall; at 17–18 d they are strong enough and claws sharp enough to cling to the cavity walls (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ). At approximately 16 d, the tips of bills can be seen at the nest hole, and heads can be seen at 21 d (133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close ).

Sex Ratios and Sex Allocation

Based on the sexing of 8,321 nestlings banded over 16 years at Riske Creek, British Columbia, there was no sex bias among fledglings at the population level (49.8% males produced from 4,144 broods) (240 Wiebe, K. L. (2023). Northern Flickers allocate female offspring to last-laid eggs consistent with the intra-brood sharing out hypothesis. Animal Behaviour 199:51–57. Close ). Older parents and those in better body condition did not produce more male nestlings (the larger sex). However, mothers allocated more of the cheaper sex (the smaller females) to last-hatching offspring in asynchronous broods, consistent with a strategy of trying to minimize brood reduction (240 Wiebe, K. L. (2023). Northern Flickers allocate female offspring to last-laid eggs consistent with the intra-brood sharing out hypothesis. Animal Behaviour 199:51–57. Close ).

The nestling phase can be divided into 3 stages with regard to parental care: (I) 0–4 d since hatching, (II) 5–14 d, and (III) 15 d to nest departure. Both parents provide care in all phases, but total nest attendance and relative contributions of male and female change. Phase I is characterized by high parental attendance and rapid nestling growth; Phase II by reduced parental attendance but sustained rapid growth; and Phase III by infrequent parental attendance and slower nestling growth.

Brooding

Data on nest temperature and thermal regulation is not available. Phase I of the nestling phase corresponds to intensive brooding because one adult is usually in the nest during the day, and the male broods during nightime hours (KLW). The number of day hours spent brooding declines during Phase II and is dependent on ambient temperature (161 Wiebe, K. L., and C. L. Elchuk (2003). Correlates of parental care in Northern Flickers Colaptes auratus: Do the sexes contribute equally while provisioning young? Ardea 91(1):91–101. Close ). When it was cold, each parent spent about 40% of their daylight time budget in the nest cavity when nestlings were 5–8 d old and brooding declined to about 20% of the daily time budget when nestlings were between 8–14 d old. Thus, nestlings could probably thermoregulate around 10 d. The amount of time parents spend inside the cavity declines rapidly after about day 15. Overall, males brooded slightly more than females during the nestling period (161 Wiebe, K. L., and C. L. Elchuk (2003). Correlates of parental care in Northern Flickers Colaptes auratus: Do the sexes contribute equally while provisioning young? Ardea 91(1):91–101. Close ) and, even when not inside the cavity, males spent more time closer to the nest (within 40 m) than females, possibly guarding the vulnerable offspring against predators.

Feeding

Parents begin to feed the young by regurgitation shortly after hatching. The pharynx of adult expands to form a crop, which is engorged, particularly with ant larvae, when the adult returns to nest. The light colored phalanges and egg teeth of nestlings help parents to locate the gapes of nestlings at the bottom of the dark cavity (241 Wiebe, K. L., and T. Slagsvold (2009). Mouth colouration in nestling birds: increasing detection or signaling quality? Animal Behavior 78:1413–1420. Close ). Both sexes feed young, usually with every visit to the nest; relative numbers of nest visits by male and female presumably reflect relative contributions to feeding. Sherman (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ) weighed single loads fed to a single nestling on three occasions: 6.4 g. According to her observations, adults make approximately 10 feeding visits to nest on day 0, and this increases to 40–50 later in the nesting cycle. The male's provisioning rate increases from about 0.92 visits/h when nestlings are young and is still brooding to about 1.9 visits/h later in the nestling period, whereas the female's provisioning rate was positively correlated with brood size (239 Gow, E. A., A. B. Musgrove, and K. L. Wiebe (2013). Brood age and size influence sex-specific parental provisioning patterns in a sex-role reversed species. Journal of Ornithology 154:525–535. Close ). On average, males provisioned at a slightly higher rate than females, especially during the mid-nestling period when the energy demand of the brood was the highest (239 Gow, E. A., A. B. Musgrove, and K. L. Wiebe (2013). Brood age and size influence sex-specific parental provisioning patterns in a sex-role reversed species. Journal of Ornithology 154:525–535. Close ). Allocation of food within broods needs further study. Over a 4.5-hour observation period at a single nest on day 17, 5 nestlings received, on average, a feeding every 54 min; 3 nestlings received 5 feedings each, 2 nestlings received 4 feedings, and the recipient of 2 feedings could not be determined (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ).

Parents, in the short-term, adjust provisioning rates to brood demands. Provisioning rates increased when the mate was experimentally removed (187 Wiebe, K. L. (2005). Asymmetric costs favor female desertion in the facultatively polyandrous Northern Flicker (Colaptes auratus): a removal experiment. Behavioral Ecology and Sociobiology 57(5):429–437. Close ); they increased when pairs were given experimentally enlarged broods and decreased when given reduced brood sizes (242 Musgrove, A. B., and K. L. Wiebe (2014). Northern Flickers increase provisioning rates to raise more but poorer quality offspring when given experimentally enlarged broods. Auk 131:571–582. Close ). However, on a per-nestling basis, nestlings from enlarged broods did not receive as much food compared to the control or reduced broods, and they declined in mass (243 Gow, E. A., and K. L. Wiebe (2014). Responses by central-place foragers to manipulations of brood size: parent flickers respond to proximate cues but do not increase work rate. Ethology 120:881–892. Close , 242 Musgrove, A. B., and K. L. Wiebe (2014). Northern Flickers increase provisioning rates to raise more but poorer quality offspring when given experimentally enlarged broods. Auk 131:571–582. Close ). Thus, brood size seems to be adjusted to parental provisioning abilities.

Nest Sanitation

Adults may eat the excrement of hatchlings when they are younger than 5 days (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ), but in general they carry fecal sacs away from the nest . At the late nestling stage, when adults cease entering nest, the excrement accumulates, but nestlings cling to the interior walls of the cavity above the compost. Fecal sacs have a thick, white, resilient outer coating and are solicited from a nestling by the adult biting at the heels or fleshy tail protuberance (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ). Both sexes remove fecal sacs, but the male usually removes more (133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close , 244 Gow, E. A., K. L. Wiebe, and A. Musgrove (2015). Nest sanitation in response to short- and long-term changes of brood size: males clean more in a sex-role-reversed species. Animal Behaviour 104:137–143. Close ). Based on videotaping at 96 nests, males removed fecal sacs during 63% of feeding trips at a rate of 1.04 ± 0.05 SD trips/h, whereas females removed fecal sacs after 42% of feeding trips at a rate of 0.7 ± 0.05 trips/h (244 Gow, E. A., K. L. Wiebe, and A. Musgrove (2015). Nest sanitation in response to short- and long-term changes of brood size: males clean more in a sex-role-reversed species. Animal Behaviour 104:137–143. Close ). Fecal sacs are carried from the nest and deposited at a distance of 100⁺ m. Widowed males decreased the rate of fecal sac removal in an apparent trade-off to invest more time in foraging for the brood (187 Wiebe, K. L. (2005). Asymmetric costs favor female desertion in the facultatively polyandrous Northern Flicker (Colaptes auratus): a removal experiment. Behavioral Ecology and Sociobiology 57(5):429–437. Close ).

Parents typically remove dead small nestlings but may leave carcasses of older nestlings (< approximately 12 d) in the cavity (KLW). At early stages (day 1 to day 10, post-hatching), parents may peck at the cavity interior to add some fresh chips to the bottom of the cavity.

Carrying of Eggs or Young

Not known in the context of parental care. There are some anecdotal reports of flickers carrying eggs out of cavities but these appear to happen after nest disturbance (e.g. 245 Baker, J. N. (1975). Egg-carrying by a Common Flicker. Auk 92(3):614–615. Close , 246 Blomme, C. (1983). Egg-carrying behaviour observed in Northern Flicker. Ontario Field Biologist 37(1):34–35. Close ) and are probably attempts to clear the nest for a subsequent nesting attempt.

Not reported.

Rarely, Northern Flickers incubate eggs of other species (e.g., Hooded Merganser (Lophodytes cucullatus), European Starling (Sturnus vulgaris), Mountain Bluebird (Sialia currucoides)) among their own eggs (247 Wiebe, K. L. (2000). Northern Flicker incubates Hooded Merganser egg. British Columbia Birds 10:13–15. Close ), but this probably results from limited availability of nest sites and cavity take-overs by the flicker rather than intentional brood parasitism.

Intraspecific (conspecific) brood parasitism does occur (see Egg Laying).

Departure from the Nest

The average age of fledging in Riske Creek was 25 days (range 21‒26; KLW), similar to that observed in Iowa, an average of 25 d (range 24‒27; 145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ). Nestlings appear to leave in the order they hatch (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ) but this needs more study. Fledglings leave the nest abruptly, usually in an initial flight of ≥ 50 m, and appear not to return (KLW). Adults increase the use of Peah and the Abbreviated Long Call just before fledging; frequency of feeding decreases, and nestlings sometimes lose weight; hunger and calling of adults probably motivate fledglings to leave nest (133 Kilham, L. (1983). Life history studies of woodpeckers of eastern North America. Publications of the Nuttall Ornithological Club 20, Cambridge, MA, USA. Close , 171 Duncan, S. (1990). Auditory communication in breeding Northern Flickers (Colaptes auratus). Ph.D. dissertation, University of Wisconsin, Milwaukee, WI, USA. Close ). Nest disturbance or threat by a predator when nestlings are nearly ready to fledge can promote flight from the nest.

Growth

Fledglings are similar to adults in mass, but their tails and wings are shorter, and they have duller and looser plumage.

Association with Parents or Other Young

During the first week after fledging, parents usually left their young at a certain location (often clinging to the side of a tree) and returned periodically to feed them (191 Gow, E. A., and K. L. Wiebe (2014). Determinants of parental care and offspring survival during the post-fledging period: males care more in a species with partially reversed sex roles. Oecologia 175:95–104. Close ). To initiate feeding, parents gave a series of soft Wicka calls that signaled the fledglings to move to the parent to receive a regurgitated meal. Between 7–10 days post-fledging, the offspring began to follow their parents to foraging sites where they either watched their parents or foraged for themselves. Based on the radio-tracking of 25 pairs at Riske Creek, British Columbia, males continued to feed fledglings on average for 16 days after they left the nest (range 11–22 days), significantly longer than females which fed fledglings on average for 12 days (range 0–21 days; 191 Gow, E. A., and K. L. Wiebe (2014). Determinants of parental care and offspring survival during the post-fledging period: males care more in a species with partially reversed sex roles. Oecologia 175:95–104. Close ). Parents did not usually split the brood, but in three of 25 cases, certain offspring were only seen with one of the parents. Males spent more time closer to fledglings (within 50 m of them) than females (191 Gow, E. A., and K. L. Wiebe (2014). Determinants of parental care and offspring survival during the post-fledging period: males care more in a species with partially reversed sex roles. Oecologia 175:95–104. Close ). After the first week, fledglings acted aggressively to their parents when their begging attempts were sometimes ignored. After about 5–30 minutes of begging without being fed, fledglings would start foraging themselves. Similarly, Sherman (145 Sherman, A. (1910). At the sign of the Northern Flicker. Wilson Bulletin 22:135–171. Close ) reported a fledgling in Iowa being denied food by its mother 22 days after fledging.

The monitoring of 26 family groups in the post-fledging period at Riske Creek showed that between 0–4 days post-fledging, the young birds stayed near their siblings, usually within 50 m of each other, and did not usually move more than 150 m during observation periods lasting one hour (248 Gow, E. A., and K. L. Wiebe (2014). Survival and habitat selection by fledgling northern flickers in a fragmented forest landscape. Journal of Wildlife Management 78:273–281. Close ). Within the first 4 days after leaving the nest, the family was located a median distance of 145 m (range 26–1,074) from the nest site. By 18 days post-fledging, the young had moved an average distance of 592 m (range 64–1,325) from the nest site. Fledglings moved greater distances from nest sites with less forest cover, and their survival rate was positively correlated with the amount of canopy cover which likely provided protection from avian predators (248 Gow, E. A., and K. L. Wiebe (2014). Survival and habitat selection by fledgling northern flickers in a fragmented forest landscape. Journal of Wildlife Management 78:273–281. Close ).

Ability to Get Around, Feed, and Care for Self

Fledglings can fly a considerable distance upon first flight from the nest, although initial perching attempts on branches may be somewhat awkward (KLW). A few fledglings attempted to forage on the ground for themselves as early as 2 days after leaving the nest, but depend on supplemental feeding from their parents for 2–3 weeks (see above).

Little is known of the juvenile life history from Preformative molt until young return to breed as 1-year-olds. In migratory populations, first year birds also migrate, but it is not known whether they do so in family groups.