23 May 2008

2 robin eggs that didn't make it

One of the most common, if not the most common, birds around here is the American robin (Turdus migratorius). The shell fragments of their bright blue eggs are frequently seen under the trees in the spring and summer.


I saw these 2 robin eggs a week ago along a path near my house. They were about 2 meters apart when I first found them, but they were probably from the same nest. Although both had been punctured, the chicks were still inside.


According to the information provided by the Cornell Lab of Ornithology (link above), on average, 40% of robin nests successfully produce young and only 25% of the fledged young survive to November. None from the nest we had above our mailbox last year survived to fledging.


John said...

Maybe the work of a blue jay? But I'm surprised it wouldn't have eaten the contents. Maybe jays like yolk better than chicks.


Jays eat robin eggs? I didn't know that.

Neil said...

Jays eat pretty much anything they can fit in their mouth, the scrub jays around here they seem to have special penchant for dog food. They work in teams: one harassing the dining canine to lure it away from the bowl, while the other will swoop in and grab a mouthful.

Still, I'm guessing that this vandalism is the work of either a house wren or a house sparrow, more likely the latter given the size of the punctures. Both are notorious for puncturing the eggs of other songbirds. Of course, there are probably other birds that do this as well, perhaps even rival robins?

adam abdulaziz said...

yh probably a jay bird. after all jays eat small chicks and eggs