Small birds (sparrows, robins, jays, finches) and mammals (squirrels, rats, opossums, raccoons) are a common sight in many urban and suburban communities with green space. However, I observe carcasses of these animals relatively infrequently.
I imagine that the following are some of the most common causes of death:
- Predation (the species I mention are small, and somewhere in the middle of the food chain)
- Age-associated decline in foraging ability, leading to starvation
- Fatal contact with infrastructure (collisions with buildings or wind turbines, contact with electricity lines)
I can think of two reasons why we don't see carcasses very often:
- predation is the most common cause of death
- individuals that succumb to disease/starvation end up in their nests/dens
Is this plausible? Has this been studied systematically, e.g. in populations of birds with tracking bands?