Feeding ecology and diet

Mimids typically have long, pointed bills; in many cases these have a pronounced downward curvature and in some species are extremely decurved. Species with especially long curved bills, such as the California thrasher (Toxostoma redi-vivum), spend much time probing in loose soil. Food is varied; for most species it is predominantly invertebrate, but small frogs, lizards, and crawfish may be taken. Substantial amounts of vegetable matter including berries and seed-pods are taken, especially, in northern species, in fall and winter. The mockingbirds of the Galápagos Islands have developed some extraordinary and unique feeding traits in response to their harsh and variable environment. On islands where there are seabird colonies, such as Hood (Española), the resident species will eat seabird eggs, cracking open eggs of smaller species (such as the swallow-tailed gull, Creagrus furcatus). The more robust eggs of boobies and albatrosses cannot be broken into, but those with cracks are immediately attacked. An even more bizarre food source is blood. Marine mammals such as sea lions, wounded in territorial battles, soon attract groups of mockingbirds, which actively drink blood from open wounds and peck up congealed blood from the ground. One visiting ornithologist recorded that he twice had to fend off mockingbirds that attempted to pick off blood spots from scratches on his legs. Other food sources include ectoparasites (often engorged with blood) and loose skin from marine iguanas (Amblyrhynchus subcristatus), disgorged fish, and other carrion and marine mammal feces. Species found on islands

A common or gray catbird (Dumetella carolinensis) at its nest. (Photo by F. Truslow/VIREO. Reproduced by permission.)

and non-breeding birds may assist in the rearing of broods of related pairs.

Was this article helpful?

0 0

Post a comment