Brewer's Blackbirds singing in the dead of night. Or more acurately, chirping all the darn time.

There is a small colony of Brewer's blackbirds that nests at the Lake each year, along Lakeview avenue. Every spring, commuters on their way to BART have to pass by The Blackbird Tree and face the Wrath of the Blackbird.

Why do blackbirds attack people? "Mobbing" is an infamous behavior of many birds, including blackbirds, where they attack a predator, either individually or in groups. Thus, you might think that this behavior serves to drive the predator away, keeping the blackbird's babies safes for anothers days. However, in Blackbirds of the Americas, Gordon Orians makes a different argument. He notes that pecking people in the back of the head (or otherwise getting macho on a predator) is NOT correllated with extra success in the baby department. So why are they wasting their time? One possibility is that they are merely showing off their machismo for the benefit of any watching ladies. Another possiblity is that birds become agressive when they have a bad bit of territory (one with humans always tramping through it), and that those extra predators in the bad territory account for the lower nest success.


Why do the Brewer's blackbirds nest colonially? One answer I read about in Blackbirds of the Americas is that they like to have a lot of neighbors so that they can spy on each other and learn where the food is. If one bird sees its neighbor returning from the Kaiser building with a big fat beakful of bugs, it knows that's a good potential source to feed its own babies. Off it goes in the same direction.