Throughout the spring and summer, you may see Swallows darting and sailing overhead while singing out their favorite songs. The beauty of their flight and harmonious sounds are a treasure in the Eagle Valley, but come October, they are out of sight, flying south in search of insects, which make up 99.8% of their diet. (Yummy!) As migratory birds, only visiting during the spring and summer months, swallows are tremendously important in helping to keep away pesky insects. These fast fliers are constantly chowing down, even while in flight! Not only are the sight of these swooping, flying marvels wonderful to see, but their insect-eating skills are also greatly appreciated.
Swallows can be identified by their short legs and bills, along with their long pointed wings and of course, their swooping and diving flight patterns. When it comes to telling the difference between the eight species of swallows, however, it can be a little more difficult. The barn swallow and cliff swallow are among the more commonly species seen in Colorado and, while they are very similar to one another, their distinct tails help to tell them apart. The barn swallow can be identified by its sharply forked tail whereas the Cliff Swallow has a more square-shaped tail. Both are fairly easily distinguished from the violet-green swallow, also commonly seen here, with its iridescent green head and back.
An easier way to tell the barn and cliff swallow species apart is by their nests. Both species build nests out of mud pellets, using their mouths, and build them in protected sites below an overhang, often in public areas like bridges, walkways, and doorways. A typical nest made by a barn or cliff swallow holds as many as 1,000 mud pellets when it’s finished, and the interior is lined with grasses and feathers. Cliff swallows are known to have their nests packed very close together in large colonies. Their nests are mostly enclosed and gourd shaped with a downward facing entrance. A barn swallow’s nest, while similar in composition, is noticeably different. Their nests are built more open and cup-shaped, and are built several feet apart from one another.
The mud based swallow’s nest is often thought of as an eyesore, and not nearly as beautiful as the birds themselves. Their nests, sometimes mistaken for beehives, are often considered to be unattractive decorations on buildings and bridges. Although debated as a nuisance, it is illegal to destroy or take down an active nest, which are protected by the federal Migratory Bird Treaty Act of 1918. Inactive nests may be taken down, and this can sometimes help to encourage swallows to find new places to make their home that are less visible to visitors.
Despite the problems with their nesting habits, swallows themselves are beautiful, magnificent little birds that entrance us with their musicality and fluidity of motion. Look out and enjoy the beauty they bring us before they take off in October for warmer weather!
Sophia Gianfrancisco is a Naturalist at Walking Mountains Science Center in Avon. Originally from Orlando, Florida, she loves being part of Walking Mountains and hopes to continue to inspire and empower others through natural science education!