"When the Swallows Come Back to Capistrano" (recorded by the Ink Spots in 1940) laments a missing sweetheart who's promised to return in spring along with the swallows — in this case, the ones migrating between North and South America, a round trip of 10,000 to 15,000 miles.

The MLP-10 garage may not be as picturesque as Capistrano, Calif. — and it's usually not as romantic — but it is home to a nest of barn swallow chicks, well tended by both parents. Hirundo rustica, known for its long, deeply forked tail, lives on every continent but Australia. American barn swallows, subspecies H.r. erythrogaster, are distinguished by their ruddy underfeathers — at least the adults are. The babies are distinguished by their egg-yolk yellow open mouths.

Adults feed on insects in flight, so are renowned for their aerodynamic prowess. To catch their prey, they execute acrobatic turns and swoops. They nest under bridges and wharves, and in barns, stables and caves. While we rush through the garage towards home, they are home, so if you are lucky enough to locate the nest, don't get too close. If you do, the parent bird on duty will swoop in and make an in-flight U-turn without stopping to feed those hungry mouths.

The family resides in a mud nest near two open passageways, allowing the parents to fly in and out at speed. In typical swallow fashion, when feeding young they rest little. Lynn Mueller, chief of grounds maintenance and landscaping, Office of Research Facilities, explains: "We've had a nice colony of barn swallows in the MLP-7 garage for years. This past winter the garage began an extensive renovation and totally disturbed the returning birds. None nested, thank goodness. Maybe the ones in MLP-10 were returning MLP-7 birds that took up residency there instead of flying further on.

"There were 11 nests last year within the middle two parking levels. The [renovation] contract was designed to begin last fall after the nesting season. However, the extent of the renovation was such that it was impossible to complete the work before this spring. Work is now nearly over and the garage will be open and ready for any returning birds next May."