Sunday, October 18, 2009

Tiny grouse indicative of wet summer



This little ruffed grouse that Sam and I got hunting the other day could be the result of all the wet weather we had last summer. It's about half the size that a young-of-the-year grouse should be at this point.


No doubt this grouse came from a hen that re-nested after its first or even second nest of eggs was destroyed by something, either a predator such as a fox or skunk or just by the weather. Grouse hens are able to incubate their clutch of 8-10 eggs in virtually any temperature, even below freezing, but there's nothing they can do if the nest is flooded which was certainly a possibility this summer.


Sam and I have taken four grouse this fall and this was the only young one. The rest were more than a year old. The ratio should be the other way around: lots of young birds and few old ones.


Incidentally, predators that destroy nests and cause some birds to re-nest actually help the population in the long. The reason is that almost all the birds will usually have their clutches of eggs hatch at the same time and consequently all their young will be exposed to whatever the weather happens to be at that time.


Ruffed grouse and most other upland birds will die if the weather happens to be cold and wet when they first emerge from the egg. So birds that are forced to re-nest after their eggs are destroyed by predators end up with their chicks emerging at a different time.


On the downside these birds are younger and smaller by the time winter sets in and have less chance of survival but sometimes, and perhaps this might be one of those years, they are the only new members of the population to have made it through the summer.


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