Monday, July 26, 2010
If you look carefully at the contents of this next box you will see three different nests. On the bottom is a piece of styrofoam placed to keep any early spring arrivals warmer. On top of it is the remains of a tree swallow's nest. This box was very busy and well defended. At least two tree swallow families fledged from here. It was fun to watch them poke their heads out as they began to explore the world outside their dark box.
But on top of the remains of that nest you can see a mass of twigs. It looks as if it's higgledy-piggledy but it is really carefully woven into a wren's nest. I had heard the wren singing and hoped that it wasn't planning on nesting anywhere near the bluebirds who had finally found a box that suited them. Wrens are not particularly kind to other birds.
This is an unusually tall nest but you can see why - these birds are small and the top rim of the nest reaches just under the entrance on the right hand side of the box. (My access is a panel on the side that is hinged at the top to allow me to lift it and clean the boxes out each year which is what I was doing when I found this.)
On top of the twigs you can barely see some grasses being woven into another nest. it looks as if was never completed. I did not have my ladder with me to examine it more carefully but it looks as if a bluebird was trying to take over the vacated space, or perhaps another swallow. I have to have one of my birding expert friends come and take a look before I get rid of this - it's a very interesting bit of nature that speaks to the wide variety of birds in my back yard, but also to their ingenuity.
Unfortunately wrens are also very aggressive birds - they have been known to kill adult and baby bluebirds and tree swallows in order to gain a nesting spot. I'm so glad that the swallows had already fledged from this box and the wren was a late comer to the neighbourhood. Who knows what will happen next spring - birds often return to their successful nesting grounds.
I've watched bluebirds for the past eight years since the boxes have been up. They show up each spring and investigate each one until they decide which is their favourite. It's often the hen that selects the one she wants. In the past two years though, the tree swallows have arrived early and driven less aggressive bluebirds away. So it was specially neat this year to have a late-comer bluebird male, determined enough to snag a nest box close to a tree swallow's box who didn't seem to mind, though she'd laid eggs and was sitting. She tolerated the bluebird male's persistent singing to lure a lady friend to join him. When he was successful, the tree swallow guarded both nests.
When checking and cleaning another box, I was completely surprised by a bunch of angry hornets who had taken it over - I got stung! Fortunately only once as I slammed down the panel and ran brushing off the black insect as I hurried away. I'll wait until winter and then remove the hive - they'll be sleeping then.
All about birds and bees this past weekend - fascinating!