Eric and I watched a couple of Barn Swallows (Hirundo rustica) gathering mud in a parking lot in Bodega Bay this morning.
I've always been fascinated by this behavior, in part because it's hard to imagine having a mouthful of mud.
Barn Swallows use mud to build their nests. Here's a picture of a male with both mud and grass (below). He flew in with the grass and then started gathering mud. Note his rust-colored forehead and underparts, and elongate tail feathers. (The females typically have paler foreheads and underparts, and shorter tails.)
Although it's a little hard to tell, this may be a female that flew in and landed behind the male (see next image). Look for the more cream-colored underparts.
Here are a few quick trivia questions about Barn Swallow nest-building. The answers are below the next image.
- How many trips per hour do Barn Swallows make while gathering materials for their nests?
- How many mud pellets make up one Barn Swallow nest?
Barn Swallows average about 30 trips/hour while gathering nest materials. It's a busy time!
A Barn Swallow nest may contain between 750-1400 individual mud pellets. Now that's a lot of mouthfuls of mud!
[Facts above from the Birds of North America account by Brown and Brown (1999).]