H.J. Ruiz – Avian101

Little Blue Heron

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White Little Blue Herons often mingle with snowy egrets. The snowy egret tolerates their presence more than little blue herons in adult plumage. These young birds actually catch more fish when in the presence of the snowy egret and also gain a measure of protection from predators when they mix into flocks of white herons. It is plausible that because of these advantages, they remain white for their first year.

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Great Blue Heron

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The primary food for Great Blue Heron is small fish. It is also known to opportunistically feed on a wide range of shrimp, crabs, aquatic insects, rodents, and other small mammals, amphibians, reptiles, and birds, especially ducklings. Primary prey is variable based on availability and abundance. In Nova Scotia, 98% of the diet was flounders. In British Columbia, the primary prey species are sticklebacks, gunnels, sculpins, and perch. California herons were found to live mostly on sculpin, bass, perch, flounder, and top smelt. Non-piscine prey is rarely quantitatively important, though one study in Idaho showed that from 24 to 40% of the diet was made up of voles.

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Brown-headed Cowbird

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The Brown-headed Cowbirds live in open or semi-open country, and often travels in flocks, sometimes mixed with red-winged blackbirds (particularly in spring) and bobolinks (particularly in fall), as well as common grackles or European starlings. These birds forage on the ground, often following grazing animals such as horses and cattle to catch insects stirred up by the larger animals. They mainly eat seeds and insects.

Before European settlement, brown-headed cowbirds followed bison herds across the prairies. Their population expanded with the clearing of forested areas and the introduction of new grazing animals by settlers across North America. They are now commonly seen at suburban birdfeeders.

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Anhinga

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Anhingas feed on moderately sized wetland fishes. In Alabama, the anhinga’s diet consists of fishes such as Mullet (fish), sunfish, catfish, suckers (Catostomidae), Chain pickerel, crayfish, crabs, shrimp, aquatic insects, tadpoles, water snakes (Nerodia) and small terrapins. In Florida, sunfishes and bass (Centrarchidae), killifishes (Cyprinodontiformes) and live-bearing fishes (Poeciliidae) are primarily eaten by the anhingas.

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Neotropic Cormorant

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The Neotropic Cormorant’s diet consists mainly of small fish, but will also eat tadpoles, frogs, and aquatic insects. Information about its prey is sparse, but inland birds seem to feed on small, abundant fish in ponds and sheltered inlets, less than 10 cm (3.9 in) in length, with an individual weight of a gram or two, such as Poecilia species especially the sailfin molly Poecilia latipinna. This cormorant forages for food by diving underwater, propelling itself by its feet. Its dives are brief, between 5 and 15 seconds. It is also known to forage in groups, with several birds beating the water with their wings to drive fish forward into shallows.

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© HJ Ruiz – Avian101