Insect-devouring swallows have important role in local habitat
My earliest memory of a bird was the one colorfully painted on a shot glass in a relative’s China cabinet with the caption “JUST A SWALLOW.”
I wouldn’t have gotten the joke even if I could read — I was 4 years old. Shots never have interested me, but just a decade later I proudly earned my Boy Scout Bird Study Merit Badge.
Learning swallow names is relatively easy. Seemingly they were named by someone wanting to help the beginning birder learn them. Among our seven swallow species here, four are named for their nest sites: Barn, Bank, Cliff and Tree. Two describe their color: Violet-green and Purple Marten. Not a single Anna’s (as in hummingbird) or Townsend’s (as in warbler) that honor people, but leave us clueless about the bird’s appearance or habits.
Our most common swallows
Swallows can be divided into two groups based on their nesting habits. Most are cavity nesters in woodpecker holes like the tree swallow or excavated tunnels like those of the bank swallow. Our two mud nesters are the barn swallow and the cliff swallow. Each constructs their nests with mouthfuls of mud carried from a nearby mudflat. Since buildings offer convenient alternatives to cliffs, cliff and barn swallows often use buildings instead. And because people know that these birds eat bothersome flying insects, swallow nests are well tolerated.
If droppings beneath a nest do prove troublesome, consider putting newspaper down to catch the waste rather than eliminating the nest. Our barn swallow in Europe and Asia is simply called the swallow since it is the only one there. It is one of the world’s most widespread bird species. Ancient Romans believed that the spirits of dead children came back as swallows so they could be close to their homes. Look for cliff swallow nests cemented beneath roof overhangs.
Each time I see a cliff swallow nest, I marvel at its beauty and the skill of its builder. Each nest represents up to 1,000 trips to the mud source. Swallows are known for their dependability for returning from the south on a specific date each year. Remember the cliff swallows that returned to Capistrano on March 19. Unfortunately, they have gone elsewhere in recent years due to repairs made on the mission church and now the town is trying to lure them back.
I eagerly await the return of the Violet-green Swallows to the Gig Harbor YMCA about April 1 each year. They fly around the roof overhang above the entrance and nest in corrugations there. Scientists have yet to discover the purpose of the rough wing. Tree swallows traditionally use abandoned woodpecker holes but often use bird boxes, as well. I once had a pair raise young in a bird box on our front lawn. Most fun was watching a bird struggling to get a large dragonfly through the entrance hole; much like a dog trying to carry a long stick through a doorway. Consider placing a swallow nesting box at the edge of your lawn or field, and monitor it to exclude Starlings and House Sparrows.
Remarkable flyers
All the swallows are similar in size and shape. The Purple Martin is largest at eight inches while the others are about six inches with long, narrow tapering wings. Their swift, wide swooping flight is a blur. Seemingly tireless, they may fly 600 miles each day, continually catching flying insects in their short, wide-gaped mouths.
The Rough-winged Swallow poses a mystery. Scientists have no explanation for the re-curved barbs on their wing’s leading edge. I wonder that the energy swallows derive from insects exceeds what they expend in flying for so long each day. They even drink and bathe on the wing while skimming the water’s surface. With each bird consuming many hundreds of bothersome and agricultural pests each day, their collective impact is significant.
JUST A SWALLOW, indeed!
Naturalist Ramblings columnist Frank Knight can be reached at frankknight@earthlink.net.
This story was originally published June 3, 2015 at 11:25 AM with the headline "Insect-devouring swallows have important role in local habitat."