Barn swallow decline has been an issue for many years. Smaller insect populations due to climate change and pesticide use may be to blame.
Barn Swallows over the Past Ten Years
My family and I have lived on two farms over the past 10 years in south-central Ontario. When we moved to our first ten-acre bungalow, barn swallows were a very common site. Our small barn had a number of nests as did the hay loft. I remember vividly mowing the lawn in the spring and summer and often feeling the wind part my hair as swallows dive-bombed the area I was mowing for the insects being disturbed. It was a surreal and yet exciting feeling watching them as they circled and then dived for the myriad of insects disturbed by my mowing. Every week I looked forward to the mowing, knowing that my friends would be there to entertain me as I laboured!Help the barn swallows! Take part in a nest watching program through Bird Studies Canada! Click To Tweet
In 2001, we moved to a 97 acre farm a few miles north of where we were. This farm had three outbuildings including an old dairy barn which we converted into a run-in for our horses and two smaller barns. Every one of those outbuildings would house dozens of barn swallow nests each year. My father also built us some Purple Martin houses. Although they did not attract Purple Martins, they did offer nesting sites for a number of bird species including the barn swallows. Again, every spring I would wait for their arrival. By the time I needed to cut the grass, there they would be by the dozens chasing the insects I disturbed.
Dive-bombing barn swallows were a common sight for our first eight years in Millbrook, Ontario. After that, I started to notice a difference. Although I noticed their return each spring, they no longer followed my lawn mower for the insects it disturbed. The barn, where my horses escaped the noon sun and biting insects, still supported a fair amount nests as did the barn behind our house. The last two years, however, have seen a more disturbing trend. Not only do I miss my dive-bombing friends, but spring is no longer heralded by dozens of returning barn swallows. This year in the barn behind our house there was only one nest. The horse barn had only two or three nests.
According to Jon McCracken of Bird Watch Canada, “In the last two decades alone, populations have fallen by over 70% in the case of Bank Swallow, Common Nighthawk, Chimney Swift, and Barn Swallow, and by over 50% for Cliff Swallow, Olive-sided Flycatcher, Eastern Wood-Pewee, Northern Rough-wingedSwallow, Eastern Kingbird, and Purple Martin.”
Possible Reasons for the Decline of Barn Swallows
- Abundance of aerial insects may be declining or their habitat range may be changing due to climate changes.
- The time of year when the insects emerge may be changing, happening earlier or later, interfering with the timed arrival of migrating species such as barn swallows.
- Use of pesticides to control insect populations may be having a bioaccumulative effect on the swallows. As the pesticides in the insects they consume build up in their tissues thinning egg shells, weakened immune systems and death due to more immediate toxic effects of pesticide consumption would have negative, long-term effects on barn swallow populations.
- Barn swallows do eat bees and as bee populations are also drastically declining, this may be a reason.
- Changes in their wintering grounds.
- Changes along their migratory paths.
Be a barn swallow nest watcher. Bird Watch Canada has initiated a program to monitor barn swallow populations. You can add important field data by counting barn swallow nests on your property and submitting that data. Register to be a nest watcher here.
Ingram, Dave. Where have all the Barn Swallows Gone? August 29, 2011. Island Nature. August 4, 2014.
McCracken, Jon. Are Aerial Insectivores Being Bugged Out? Bird Watch Canada, Winter 2008, Iss48. August 4, 2014.
Update: It is now August of 2016. This year I could find no breeding barn swallows on our property. Last year we still had a few nests. It is a sad testament to the plight of insectivorous birds in general I believe.