Thursday, April 15, 2010

Nesting Swallows

If you've driven under 290 recently, you've probably noticed that the edges of many of the freeway's
underpasses are decorated with scores of swallows' nests. On my way to work yesterday, I stopped to take a closer look at some of these.

As you can see, each nest is made of lots of small balls of mud stuck together to form a jug-shaped nest.

While I was looking at the nests, several swallows kept flying in and out of them. I wasn't sure whether the birds were Cliff Swallows or Cave Swallows, because these two species look very similar: Essentially the only difference is that Cliff Swallows have a white forehead while the forehead of Cave Swallows is rusty brown.

Unfortunately, the birds were flying too fast for me to see their heads clearly. So I took a series of photos, hoping some of these would show the swallows' foreheads.

Only a h
andful of the photos were even partially in focus and most of these didn't help, because they showed only the birds' backs.

However, I finally got one picture that settled the ID issue. The birds were Cliff Swallows.


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