Friday, February 11, 2011

Historical storm research and today

We all know climate and weather have a big impact on the birds. This harsh winter has shown us what the snowiest January ever and historic snow depths does to bird populations. Soon the spring warmth will allow migrants to reclaim what has become our own arctic tundra. In the fall, cold fronts signal ensuing large raptor flight days. Individual low pressure systems and thunderstorms, isolated weather phenomenon like this amazing event I chronicled last June, are very underrated in terms of impact in my opinion. We can monitor some of the direct outcomes from storms, like seabirds being blown in by a hurricane, relatively easily. Others, like what will happen this spring because of the damage to the McKinney Refuge and Stratford Great Meadows, are more difficult to gauge and require devoted field work and careful surveying.

On April 29, 2007, I found a very rare vagrant Purple Gallinule in a pond in Stratford. It was hypothesized rather quickly that it had arrived here from the southeast U.S. via a strong nor'easter on April 16th. It came from the Gulf of Mexico area, exiting off the Carolina coast and riding up through New England. The surface map from 7AM on the 16th is below.

That was easy enough because we witnessed it. Finding out what happened in the past, when much less was known and recorded about birds and the weather, is much more difficult. One can occasionally come up with nice answers. There is a record of a Purple Gallinule in Bridgeport on June 26, 1903. I wanted to see if I could come up with a storm to explain that bird's arrival in nearly the same location. I did - the following image is a surface plot of a storm on June 12, 1903.

This storm was weaker, but followed nearly the exact same path. It also moved very quickly, able to carry that gallinule up here before it was severely injured or killed. One of the keys of both storms was that the low pressure center came nearly due south of this part of the state, pushing the birds in to us perfectly as it rotates in a counter-clockwise direction. Imagine all of its winds and rain spinning in that manner and you can visualize how any collected birds would make landfall right on our doorstep.

In 2011, we have all of the pieces of the puzzle in front of us. We only need to put them together to start determining every single one of the links between birds, climate, and weather events. I really hope we can devote the time and acquire the money we need to study what will happen in the McKinney Refuge this spring after all that destruction.

Images via and copyright NOAA and the NWS

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