Mike and I sat on our deck basking in the warm and rare May sunshine. All of a sudden the first Tree Swallows of the year came swooping through the sky above our front field. They were about a week later than most years, but considering the weather of the previous week, it was not a surprise and maybe they should have waited even longer. Yes, it’s been a very unpleasant stretch of cold and even one snowy morning here in east central Minnesota and the mood of the people is not improving, but the birds continue to forge onward, instinctively confident that spring WILL arrive one of these days. For the swallows, providing bird seed is not beneficial since their main food source is flying insects.
A pair of Tree Swallows perch together and their iridescent blue wings sparkle in the sunshine.
That afternoon, as we watched and listened to the graceful little blue and white birds, I realized I hadn’t cleaned out the nest boxes they would soon be investigating. So I grabbed the step ladder and went out into the field and began the process of opening the boxes and removing old nests, or nesting materials. I discovered one that had obviously been used by a House Wren. Twigs of assorted sizes filled the entire interior of the box. Another had a tight cup of grasses and feathers – a typical Tree Swallow nest and a third had the makings of a Bluebird nest. Whether these birds were successful in raising their babies we can’t know, but there was an abundance of droppings at the edge of some nests to indicate the young reached the fledgling stage.
There is always a bit of excitement and anticipation associated with this process of nest box preparation. We are always hopeful that the weather will cooperate and assist the birds in their annual efforts to renew their species. Too much rain or cold temperatures slow down the insect populations that these birds depend upon to feed their young. Too much heat can kill the young in the nests.
Even more dangerous are feral cats or housecats left to roam freely, especially in the spring. Right now there is a feral cat living somewhere near us. One afternoon Mike looked out a living room window and saw the cat tiptoeing back towards our barn with a red squirrel in its mouth. Songbirds, especially 
those nesting in boxes are very vulnerable to this predator. A cat can leap and snatch a parent bird right out of the air as it returns to the nest. Patient and highly observant, it can also wait for the critical day when the fledglings leave the nest and flutter feebly to the nearest tree or shrub. One cat can take a terrible toll on our bird populations.
I thought about this problem while I was moving from one nest box to the other, and the swallows were swooping around the field, chittering in their cheerful way. One seemed especially interested in what I was doing and as I climbed down the step ladder, it swept over my head. These swallows may or may not be the ones who nest in our field each year. In fact, I think they may be the vanguard of those to follow. Like so many other species of birds, there are always the big risk takers who arrive first seeking the best nesting territories. Sometimes the gambit pays off, but other years, when the weather is especially volatile, it could well be deadly.
Tree Swallows and Bluebirds compete for the same nests – it is quite unusual to see the two living so close to one another.
There is usually competition between the Tree Swallows and the Eastern Bluebirds over a couple nest boxes, but somehow they come to an understanding and each species finds a home for the season. May it be the same this year. This hobby or habit of bird watching provides us with so many different avenues for learning – every day can provide new insights.
By Kate Crowley
