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Double-crested Cormorant

Phalacrocorax auritus

Order:
Suliformes
Family:
Phalacrocoracidae
Sections

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Figures

Figure 1. Distribution of the Double-crested Cormorant.

This species also winters in Bermuda in small numbers, and winters locally south to the dashed line. See text for details.

Fig. 2. P. a. auritus has black crests, as shown here.

P. a. albociliatus has mostly white crests. Drawing by N. John Schmitt.

Fig. 3. Double-crested Cormorants dive for their prey.

Double-crested Cormorant swimming underwater. By N. John Schmitt, adapted from Johnsgard 1993.

Fig. 4. Right foot of Double-crested Cormorant showing totipalmate webbing.

Drawing by N. John Schmitt.

Fig. 5. Double-crested Cormorant spread wings to dry their feathers.

Wettable plumage reduces bouyancy, an advantage in underwater diving. Photo © Brian E. Small.

Figure 6. Male advertising nest site (Wing-Waving display).

Drawing by N. John Schmitt, adapted from Johnsgard 1993, after Van Tets 1959.

Figure 7. Annual cycle, Ontario.

Annual cycle of breeding, migration, and molt of Double-crested Cormorants from northern populations (Ontario). Thick lines show peak activity; thin lines, off-peak.

Figure 8. Double-crested Cormorant nest become built-up after years of use.

Drawing by N. John Schmitt.

Figure 9. Rare phenomenon -- crossed-bill.

Phenomenon may be related to contaminants in the diet. Such individuals do not survive independently. Drawing by N. John Schmitt.

Figure 10. Relative abundance of the Double-crested Cormorant during the breeding season, based on BBS data.

Based on data from the Breeding Bird Survey, 2007-2011. From Sauer et al. 2014, see text for details.

Figure 11. Regional trends in Double-crested Cormorant populations, 1966-2011; data from the Breeding Bird Survey.

Data show best estimates of population change for the species over its range; from Sauer et al. 2014, which provides details.

Figure 12. Early winter density of the Double-crested Cormorant, as determined by data from the Christmas Bird Count, 1980-2006.

Numbers show the number of individuals counted per 100 party hours in each region with CBC count circles.

Recommended Citation

Dorr, Brian S., Jeremy J. Hatch and D. V. Weseloh. 2014. Double-crested Cormorant (Phalacrocorax auritus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA. https://doi.org/10.2173/bna.441