Bird of the week 2: American Robin, Turdus migratorius

January 27th, 2008

The last week’s bird was the Eurasian Robin. This week I will cover the American Robin. Judging by it’s name, one might think that the American Robin is a close North American relative of the Eurasian Robin. They both share the orange breast. And that is the reason why Europeans, who first came to North America named the bird Robin, because it reminded them of the well known bird from their homes. But the North American Robin is a much bigger bird than the Eurasian species. It’s about the size of a Eurasian Blackbird (or just Blackbird in Europe). Those two species are in fact much more closely related than the American and the Eurasian Robin. Both American Robin and Eurasian Blackbird belonging in the Genus Turdus (Thrushes).

The American Robin is one of the most common birds in North America. It has adapted very well to human settlement, now being a familiar sight on most gardens over North America. But they also continue to live in forests. I saw the species in the city of Bozeman (Montana) but also in the remote wilderness of Yellowstone National Park.

The size of the Robin is about 23-28cm, a typical size for many of the bigger thrush species. Their weight is on average about 80 gramms, with more northern birds on average being slightly heavier. Their wingspan is between 35 and 40cm.

Similar to the Eurasian Blackbird, the American Robin feeds mostly on invertebrates, especially earth worms but also caterpillars or grasshoppers. Beside invertebrates, fruits are very important, especially outside of the breeding seasons. The young in the nest are mostly fed on worms and similar animals.

American Robins built their nest in bushes, between 1 and 5 meters above ground in which the female lays between 2 and 5 (normally 3-4) blue eggs. After an incubation period of about two weeks, the young spent another two weeks in the nest before leaving the nest. Outside the nest, the young follow their parents and continue begging for food. Immediately after leaving the nest, the young are not yet capable of flying like the adults. This will take another two weeks. American Robins breed between two and three times a week.

Enemies of the Robins are cats and other smaller mammals, but also snakes and raptors like the Sharp-shinned Hawk, Cooper’s Hawk or Northern Goshawk. Young Robins are often eaten by snakes, squirrels, crows or Blue Jays.

Over the northern part of it’s range, the American Robin is a migratory species (hence it’s scientific name migratorius, or it’s German name Wanderdrossel - Wandering thrush), spending the winter further south in the USA or Mexico.

The population of the American Robin is stable or increasing over most of it’s range. Some sources say that there are over 300 million individuals. As with most bird species, pesticides can have a negative effect on individuals or local populations.

The species sometimes crosses the Atlantic and reaches Europe. Those vagrants often attract huge “flocks” of birders, especially in Britain. But sometimes the birders arrive too late. There is at least one story about a American Robin being eaten by a Eurasian Sparrowhawk before many birders could see the bird.

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