Saturday, July 11, 2009

And Then There Were None

Last year a pair of Barn Swallows built a nest under the peak of our roof. Last year's nest was reoccupied this year. They say nesting pairs often return to the old nest, so maybe these are the same birds. Pairs typically are monogamous and the male is very protective of the female, fighting off any other male interlopers.

I know Barn Swallows build mud nests in some locations, but here it is a mixture of mud and grass. They pick the most precarious spots. The one under our roof has no support other than a 1/2 inch ledge of wood near the eves. Somehow they are able to concoct a substance sticky enough to hold everything up straw by straw. I've been watching our nest with binoculars and recording the developments on film.

On June 30 (the 1st shot), there were five chicks in the nest. Then on July 2 (the 2nd shot), there were only four. On July 4 (the third shot), the number had dropped, this time to three. One of the three was definitely smaller than the other two. Then on July 5 (the 4th shot), we were sitting on the front porch. We heard a loud thud on the tin roof. Wayne went up the ladder and found a chick below the nest. Further inspection led to the discovery of two additional dead chicks in the gutter.

We weren't sure what was happening. Was it sibling rivalry or were the chicks just getting too big and falling off the edge? After all, it's pretty precarious up there. It made us sad and a bit afraid that the mother bird might abandon the last two, but so far so good. Some web research indicates that barn swallows may lay their eggs asynchronously (over time) and start incubating the first eggs before the last are laid. This can result in larger siblings who are more aggressive and kill their "younger" and smaller siblings (siblicide). Not a very pleasant thought.

And that's not the end of the story. We returned to the cabin after a day in town. There were no chicks left in the next. We don't know what could have happened. Maybe the metal roof just was too unforgiving for their first flight.

Have you had any experiences like these? I'm curious what might have happened in the end. -- Margy

1 comment:

  1. We had the violet-green swallows nest at our home in the Willamette Valley for many years. One time one of the chicks fell from the nest and we were able to gently pick it up with a kleenex and place it back in the nest. The parents seemed grateful! And they always left over the July 4th holiday - we would be gone camping and come home to their emtpy nest. They also arrived on the same day each spring, just a couple of days after the large group returned to Capistrano.