Thursday, January 17, 2008

New Visitors to the Minnesota Valley NWR

After work on January 10th I stopped in at the Minnesota Valley NWR visitors center to check out their feeder stations. I do not usually like to photograph birds at feeders, I prefer to shoot them in their natural habitat, but in Minnesota in the middle of January it is really hard to find birds any where else. Besides there is a sharp-shinned hawk that has been frequently hunting at the feeder station through out the winter. While the feeders may not be the sharpies natural woodland habitat there is certainly no one at the refuge that is filling a feeder with juncos and downies to try and attract sharpies.

On this trip the sharpie was not around while I was there. Most of the usual southern Minnesota winter birds were around. I saw juncos, cardinals, tree sparrows, white-breasted nuthatch, plus downy, hairy and red-bellied woodpeckers.
There were also a couple of new arrivals that I have not seen in my visits over the past month or so. There was a large flock of European starlings. Starlings were fairly common in the fall but have been somewhat scarce lately. On most of the CBCs that I participated in this year there were always quite a few less starlings then I expected.Starlings are an introduced species in North America and are very competitive with native cavity nesting birds for nest sites. Because of this fierce competition many birders believe that starlings have contributed to the decline of these native species. This has caused many birders to feel some animosity towards starlings. However the other new arrival to the refuge feeder usually inspires even more animosity then the starlings.
The brown-headed cowbird is the only nest parasite that is common across North America. Cowbirds do not make any nest of their own. Instead the female lays her eggs in the nests of other birds who often end up raising the young cowbird. The female cowbird will often remove an egg from the nest before laying her own which reduces the number of offspring that the host bird will produce. The cowbird eggs typically incubate more quickly, 11 to 12 days compared to 12 to 17 days for the host bird, so the cowbird eggs hatch earlier giving the fledgling cowbird an advantage over the other birds in the nest. The cowbirds are usually larger then the host bird which also gives the cowbird fledgling an advantage. If the host bird discovers the cowbirds deception and removes the cowbird egg the cowbird will some times return and destroy the nest as well as any of the host birds eggs or chicks.

Many people consider both starlings and cowbirds pests however I do not agree. I do not consider these birds pest I consider them sharpie food. Hopefully I will get a chance to see the local sharpie do his part to control the population of both of these species.

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