Monday, August 4, 2014

Nesting Song Sparrows

It is natural for one of my garden fence posts to be topped by a Song Sparrow.  Through most of the spring and summer, a Song Sparrow uses this perch to sing his song of ownership over a prime nesting territory.  The bounds of that territory may match the garden fence, because the nests are mostly to be found somewhere in the garden.

This juniper seems to be the preferred location of the first nest of the season.  That’s probably because this shrub is the best source of cover early in the year.  Had it not been for the sparrows, I would have removed the juniper long ago.  I do trim it back severely each year so it doesn’t take up too much gardening space.

The pruning tends to make the branches more dense.  I can hear when a nest is active, but finding the nest without disturbing it is nearly impossible.

It’s after the fact that I discover the nest locations.  This shot is from the same angle as the last.  I just pulled up the concealing branch. 

The nests always seem to be sandwiched tightly between two branches, with the top branch making a low ceiling over the nest.  This makes the nest quite well hidden and difficult for most predators to approach.

Sometimes the birds will choose a location other than the juniper for their second nesting attempt.  Severe downdraughts from a powerful thunderstorm laid over a portion of this stand of Ashy Sunflowers.  The result was a tangle of horizontal stems close to the ground.

A couple weeks after the storm, I was trimming back some of the fallen plants to keep them from interfering with corn growing in a neighboring bed.  I stopped my work when I noticed a wad of grass seemingly stuffed between the stalks.  The grass should not have been there.

The grass I had seen was part of a Song Sparrow nest.  A couple of the stalks I had already cut had formed part of the roof over the nest, so the nest was more exposed than intended.  I bent a couple of fresh stalks over the nest and wove them in with the others in an attempt to repair the damage I had done.  Then I left the area alone for a few days and hoped that the sparrows would accept my alteration of their original design.

Apparently I was successful.  When next I checked, young birds were growing nicely.  If there was a problem, it was being caused by the wind blown plants attempting to return to a more upright position.  The shifting plant stalks had moved the nest about 30 degrees off level.  The nestlings seemed comfortable in their slanted home and were old enough to adjust their positions to match the new attitude.  Song Sparrow nestlings leave the nest about ten days after hatching, so these only had a few more days left in the nest anyhow.

One day I came out and heard young birds calling from the nearby field.  I checked the nest and it was empty. 

Although I could clearly hear the young birds calling for their meals, they stayed out of sight down in the grass.  The adult birds were seen busily searching for insects to deliver to their offspring.  It’s hard to tell how many sparrows have been produced from my vegetable garden.  I am assuming that it is the same male that comes back each year to this particular spot.  I once read of a male Song Sparrow that returned to the same nesting area 16 years in a row.  I hope my bird can match that longevity.

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