Every year, on one of my nestbox trails, I usually give a nickname to an individual parent bird that shows unique behavioral characteristics. All of these nicknames have had affectionate intentions, but not all names have been worthy of publication. I have written about some, such as “My Little Chickadee” that used to cuss me out at each monitoring visit after I had banded her one night, and “Macho Man,” a very aggressive male bluebird that always dove at me as I monitored his families over the years.
Nonetheless, during the 2016 nesting season, I have gone the extra mile to assign a nickname to an entire species. I now call Tree Swallows “Zika Busters.” The Zika virus has been in the news before and after it was found in mosquitoes in southern Florida. Transferred to humans in mosquito bites, this virus causes microcephaly in newborns and has become a nightmare in infected countries. The media reports on Zika’s presence, insecticide use, the release of sterile mosquitoes designed to diminish mosquito populations, medical treatments, consequences of being infected, the quest for vaccines, and everything else being done to stop Zika’s progress. Of course, the ultimate objective of all health departments is to wipe out the Zika virus altogether. According to the Center for Disease Control website, Zika is found in all countries in Central and South America.
So far, the media has not mentioned birds as a partial solution to stop Zika, and of course, birds can’t stop the entire threat, so why am I calling my Tree Swallows Zika Busters? Individual Tree Swallows can snatch infectious mosquitoes from the air and therefore protect individual human beings from being infected. Tree Swallows can slow the rate of Zika infection when they dine on mosquitoes.
While I monitored my nestboxes in Delaware County Ohio that raised 900 Tree Swallows in 2016, I never had to apply insect repellant because my swallows took care of the mosquitoes and deer flies for me. The only time I had mosquitoes attack me is when I returned to my own yard in Delaware where I have no Tree Swallows.
Citizens in Central Ohio don’t have Zika to worry about, but we do have our own mosquito-borne diseases. The Delaware General Health District has a free brochure entitled Mosquito-borne Disease; West Nile Virus; La Crosse Encephalitis; St. Louis Encephalitis. The pamphlet describes each disease, its transmission and symptoms, along with prevention techniques. After reading about these local threats, I will have a more liberal attitude toward applying insect repellant in the future.
Tree Swallows in Central Ohio fledged most of their young by the last days of July, then they staged to form flocks that may have drifted north a bit, but then they got serious about heading south and their historic migrations through Ohio usually end by mid-October. Any good bird book will show that Tree Swallows winter near the Atlantic coast in South Carolina, Georgia and most of Florida, while others winter along the Gulf Coast and into Mexico and Central America. Swallows also spend winters in the lower third of California’s Pacific coast, and some cross the Atlantic Ocean to winter in Cuba, Haiti and the Dominican Republic.
My projects’ contribution to prevent mosquito borne diseases in 2016 not only includes 900 swallow fledglings from 278 nests, but more than 265 pairs of parents. Tree swallow adults can consume up to 2,000 insects a day because 99% of their prey is less than 10 millimeters long, and that’s half the width of a nickel. And, most importantly, 90% of the time, Tree Swallows hunt below 39 feet where we are. One study found that 95% of insects in the Tree Swallow diet are from the order Diptera and sub-order Homoptera. Mosquitoes are in the order Diptera along with flies, gnats and midges.
To sum things up, I have no doubt that my hobby of raising Tree Swallows is helping to keep fellow humans healthy, here in Ohio, and our neighbors to the south and across many borders. I do what I do for the birds, but when my hobby also benefits people, that is icing on the cake.
Other swallow species also dine on mosquitoes. Each swallow species has its own menu of prey species and specific altitudes where they hunt, along with when and where they migrate. So if you raise Purple Martins, protect Cliff Swallow nests, leave barns open for Barn Swallows, or just watch Bank Swallows and other flying-insect-eaters, smile because these birds are keeping members of our species healthy.
Conserve on for a healthier world!