Cormorants are large waterbirds, with webbed feet, long necksand hooked bills. They spend most of their time swimmingunder water to catch food (mainly fish). Off of theNorthwest coast of North America we can commonly see three speciesCormorants (Double-crested (DC), Brandt’s (B) and Pelagic(P). What is interesting for this question is that theyall appear to be hunting in the same area. The threespecies have nesting sites on three different rockyislands. They make a nest of stones and debris, usuallyon a flat rocky surface. Before heading out to feed inthe mornings, Cormorants regurgitate a pellet of indigestible partsof what they have consumed. All of the birds are capableof diving to depths of 100+ feet.

A research team would collect the pellets and record what theprey items were for each species.

Brant’s: virtually all small, bottom dwelling fishthat live in and on the bottom sands and gravel that extend out todepths of 75 feet.

DC: exclusively small schooling fish from midwaters(depths from 1 to 50 feet).

P: virtually all fish that live in and among shoreline rocks and boulders, depth of 3-15 feet.

1. what principle of ecology appears to be violated by thesebirds?

2. what evidence suggests how theyare avoiding competition and how are they doing this?

Answer rating: 100% (QA)

1 The principle of ecology that appears to be violated by these birds is the Competitive Exclusion P... View the full answer