Nesting News

A week ago, I posted about the Tree Swallows in the nesting box, with 5 eggs. Dave checked on the box last night and there are still five eggs, but nothing has hatched. And now the eggs are in a different spot and feathers have been added. We also saw the Tree Swallows mating last night and then going back into the same box. Dave isn't sure, but is wondering if they started over and rebuilt a nest over top of the eggs we observed last week.



Another note of concern is that it looks like one of the eggs may be damaged, possibly pierced? The House Wrens are back and have built a nest in another nesting box. Last year, the House Wrens, Tree Swallows and Robins were all sitting on eggs about the same time. I was worried about the House Wrens getting at the other birds eggs/young, but it didn't seem to be an issue last year. Is the small hole in the egg on the far right a piercing from the House Wren?



"A House Wren weighs about as much as two quarters, but it’s a fierce competitor for nest holes. Wrens will harass and peck at much larger birds, sometimes dragging eggs and young out of a nest site they want – even occasionally killing adult birds. In some areas they are the main source of nest failure for bluebirds, Tree Swallows, Prothonotary Warblers, and chickadees." (http://www.allaboutbirds.org/guide/House_Wren/lifehistory)

So I'm wondering, would the Wren even bother with the Tree Swallows if they aren't competing for a nest site? The Tree Swallows returned to their same box and the House Wren went back to the one it used last year, and there is some distance between the two. Or is the damage to the Swallow egg something else? The entry hole to the nesting box is too small for a Starling. Could it be a House Sparrow? Any thoughts/ideas you have to share are appreciated.


The House Wren nest: