The other day, the water in our backyard birdbath (Eastern US) had become fairly murky. So my wife cleaned it out and replaced it with fresh. Seemingly immediately began an amazing run on the thing. Robins, sparrows, finches , wrens, and catbirds all took their turns splashing and fluttering. At times they even queued up for their shot at a bath.
This got me wondering, are birds affirmatively more attracted to apparently clean water than to more dingy stuff? An easy evolutionary explanation would be that clearer water might be less likely to contain dangerous organisms.
Our experience here hardly counts as a controlled experiment, not least because the water was changed shortly after I had restocked our feeders, so the increase in bathers may simply have resulted from the larger number of birds drawn by the newly available food. But I have never before noticed such bath mania after I have filled the feeders. On the other other hand, it hasn’t rained here in maybe two weeks, so that could be another confounding factor.
But we have had birdbaths in our yard for decades (including the one in question, and in the same location) and we don’t recall ever observing a similar rate of use. Thus my question, which I paraphrase here: does water’s clarity affect its attractiveness to songbirds?
(I’ve done some Googling but turned up nothing.)