A week ago I reported on the Cordillerans nesting on my front porch rafter. At that time I mentioned that the pair (or perhaps just the female) had moved 2 eggs out of the nest and put them in the corner. This was on July 8th.
On the 10th, I checked again and there were 3 eggs in the corner and a nestling in the nest! The literature (BNA) states that incubation runs from 14-16 days for this species. They started incubation on the 24th of June. So that puts hatching at or around the 16th to 17th day. I don't see any information in BNA concerning this egg-removal behavior. Can someone shed some allegoric or anecdotal information on this? Do they somehow detect infertile eggs, and therefore remove them? Do other species knowingly practice this behavior and for what reason? And instead of taking them off and dropping them away from the nest, why just put them in the corner of the nest and the rafters (is this just the easiest place to put them?)? It seems that they removed one egg per day (I know the first two were removed one day apart, but then I had two days where I didn't check the nest, upon which I found the third had been removed and one hatched!) - why remove one per day and how did they get it right on leaving the single fertile egg? Assuming that infertility is the reason they removed the other three. Nothing but questions. Well - I am happy. I know that the probability of a species reusing a nesting site/area goes up if the previous attempt was successful and probably goes to zero if unsuccessful. So I have a chance of annual repeat performances. Jeff J Jones ( <mailto:[email protected]> [email protected]) Teller County - 8500' - Montane Woodlands --~--~---------~--~----~------------~-------~--~----~ Colorado County Birding: http://www.coloradocountybirding.com/ You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.as/group/cobirds?hl=en -~----------~----~----~----~------~----~------~--~---
