Question

Researchers observed that the crows only gather and drop the largest whelks. What are some reasons crows might favor larger whelks?

Short answer

The crows mostly prefer larger whelks. Higher caloric content is there in larger whelks for crows compared to the smaller ones.

Step-by-step solution

Crow

The large and glossy blackbird found in almost every variety of habitats in the world that helps in controlling pests and serves as seed disperser is called a crow.Examples of crow include common raven, hooded crow, western jackdaw, carrion, pied, brown-headed, white-necked, grey, pal, and long-billed crows.

Some bodily features of the crow are strong toes, strong legs, shiny black-colored feathers, thick beaks, and loud voices. Some food sources of crows are nesting birds, carrion, snakes, snails, fish, insects, and mammals.

Whelk

The slow-moving marine snails primarily found in temperate water and feed on mussels, worms, and crustaceans are called whelks.

Some of the physical characteristics of the whelks are that they are a species of shellfish; they have hard shells, soft bodies, broad aperture, and long siphonal canals. Some predators of whelks include birds like crows, crabs, and gulls.

Crow favoring larger whelks

Whelks acts as prey for the crows. These large birds break open the shells of the whelks and consume the meat, such as the snail inside the shell.

The energy gain is higher in the break opening of larger whelks; smaller whelk requires more effort by a crow to break it open and gives lesser energy gain.