Good year for bluebirds and swallows

Where do feathers go once a bird sheds them? Millions of birds, billions of feathers, and how many feathers do you see lying around? A reader of my Home and Garden Section column (StarTribune, Wednesdays) asked that question recently. My answer: I don't know.

The question came the day after I had done fall housecleaning for the bird nest boxes I maintain at a golf course near our home. I remove the used nests, and sweep out debris. We have 47 boxes in place.

(We had almost 70 percent nest-box occupancy this year, by the way, about 15 points higher than the average for the past six years. The warm, wet weather was very good for the insect populations on which these birds feed. Fledged from these nests were 75 Eastern Bluebirds, 72 Tree Swallows, and an uncertain number of House Wrens and Black-capped Chickadees.

Feathers enter here because the swallows always incorporate feathers into construction of their nests. It's believed they use feathers as insulation. You'll fine two feathers, six, perhaps a dozen or so in a swallow nest. This year I opened a box to find almost nothing but feathers. I counted them once I had the nest on the ground: 73 feathers, most of them from either ducks or chickens. There was one bluebird feather, one American Goldfinch feather, and one feather from a Downy Woodpecker. A few other nests held songbird feathers; most of the feathers were from non-songbird species.

The golf course is at the edge of Wayzata. I know the area around the course well. I have no recollection of seeing chickens or a property that even looked like it might have chickens within two miles of the course and these swallow nests. So, just how far do these birds fly to find feathers? How long does it take them in the spring to find a source? Ducks are easier to find, certainly, but even the dozen Wood Ducks courting on our swampy pond this spring left few feathers to be seen. So, again, questions I can't answer. That's one of the reasons I like birds – always a new question.

The photos below were taken the day I cleaned nest boxes.

Tree Swallow nest containing one egg. Note the feathers. The nest was abandoned after the lone egg was laid. This happened most likely because the hen died, either from predation or starvation. The latter could occur during a prolonged wet period that made it difficult to find the flying insects on which these birds feed.

Two of the smaller feathers from that swallow nest that contained 73 feathers.

Eggs from an abandoned Black-capped Chickadee nest. Two eggs are punctured, most likely by a House Wren, a competitive and aggressive species when it comes to territory. I assume the nest was abandoned after that attack.