great crested grebes loan parent

tigertom · #1 (**permalink**) 13-07-2011, 10:08 PM

on my local lake have noticed that that one of 2 grebe parents is no longer on the lake and has been gone for a few days now the one that is left has got 2 young ones thay are not that far awy form starting to fly the one parent is still feeding them, will it be able to cope and would it be normal for one of them to leave like this,

Dogghound · #2 (**permalink**) 14-07-2011, 12:01 PM

It could be one of a number of things, it is most likely linked to the fact that great crested grebes split the brood between the two parents once they get to about 6 weeks old. However occasionally when there are only two (or obviously if there is one) the brood is not split. The adult usually leaves shortly after the young is independent. It could be that they split the brood and one of the young developed more quickly/or was predated and the other parent has left to undergo its post breeding moult. Or both parents could have reared the 2 young and one (most likely the female) has gone away to moult. The bond between the adults tends to break apart around this time of year (or when dispersal of young starts). They are a rather complex bird when it comes to rearing of young, they often have a favourite chick which they feed more than the unfavoured one.

So in answer to the question yes it will be able to cope and yes this is perfectly normal.

tigertom · #3 (**permalink**) 14-07-2011, 03:22 PM

Thanks for that dogghound I had noiced that they have split young in other years though this year they did not, its the 1st time they have only had two young on this lake, they normaly raise 4 is lake is full of roach an rudd not sure why only two this year maybe new pair

Dogghound · #4 (**permalink**) 14-07-2011, 03:27 PM

They could be inexperienced birds, they tend to breed in their second summer but 1st summer birds occasionally attempt it with mixed success. Therecould have been problems with the roach (prey) population, eggs may have not ha predated. You can only speculate.

tigertom · #5 (**permalink**) 14-07-2011, 08:13 PM

I think may well have been problem with eggs plenty of roach and rudd and small perch {thats what they were feeding to young at 1st} one of the parents was sat on nest with the 2 young on back for about five days after they hatched. though this pair did act in same way as grebes have befor on this lake to cormorants that was attacking them from under water cormorants dont like being speared in in the breast, the anglers on this lake like the grebes very much.