House Sparrows and broods

Obviously, I am talking a lot about the House Sparrow. That’s because these days I sit and watch them out the window. In our last post, I told a little story of how our House Sparrow mates were building a nest to lay eggs. After I wrote that, I saw a juvenile:

Beside that juvenile is its mom. So, I wondered, perhaps she is taking care of this one while she is preparing to lay more eggs? There is actually a book on House Sparrows called “Biology of the Ubiquitous House Sparrow” by Ted R. Anderson. In it, he remarks that House Sparrows can lay multiple clutches per breeding season. He also points us to another book by Summers-Smith called “House Sparrow”, where that author indicates that House Sparrows do indeed feed their fledglings while preparing to lay the next brood.

He also points out that the number of broods per year seems to depend on latitude, going by previous studies, although I do not think a systematic study has been undertaken to show this in a rigorous statistical fashion. One example is Spain where Veiga reported that the average was 2.37 broods per year. The location of that study was about five degrees south of here, although I suspect climate may be more important than just latitude.

Mom with juvenile behind her: I verified it was the juvenile with my eye

So, I will continue to observe my friends and report on them. They always seem to stop for a little while on a very nice branch for taking their picture and I wonder if they have come to expect me to do that? Probably not.

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