The Lincolnshire Bird Club

An interesting development at Grantham today.....see http://www.lincsbirdclub.co.uk/pegcam.html

Bob managed to get a snapshot of two birds together feeding the chicks at the same time early this moring. These appear to be two adult females !!

Whilst it is not unknown for a previous season's fledgling females to help out the following year, our two birds appear to be both full adults. i.e. more than two years old.

Alan

What a coincidence. While out this morning in central Lincolnshire with Andy Sims we watched a marsh harrier carry a small prey item to the area where we thought it had a nest and another marsh harrier came up from the vegetation and a food pass occurred after which the recipient went back to the nest. Not particularly unusual except both birds appeared to be adult females and an adult male was circling around them as it happened. In the brief time we could see both birds involved we could see no difference between them.
As marsh harriers are polygamous I thought that possibly 1 female had lost her brood and was helping the other female, both of which were mated with the same male. Neither of us had seen this before. Any alternative explanations?

an alternative is that the alpha female actually robbed the beta female of the food; I have seen this happen when a male takes prey to the beta female and she is mugged before reaching her nest by the alpha female -- males will usually feed the alpha female first but will obviously spread the food load to try and rear as many chicks as possible; when nests are close together there is more chance of interaction and this is worse of the male's preferred hunting area sees him passing over the beta nest to get to the alpha nest;
as both looked like adult females, adult and immature females are hard to age and separate, it seems that neither was a 2cy male but in recent years I have come across quite a few 2cy males actually nesting and they can be very female like in plumage with the underwing pattern being the easiest feature to identify them as males at this age.

http://pewit.blogspot.com/2011/06/marsh ... d-sex.html

http://pewit.blogspot.com/2011/06/pic-of-week.html

http://pewit.blogspot.com/2011/06/lover ... -away.html