Something obscene happened at the tip of Point Pelee today. I'm not even going to mention it (but congrats to those who saw it!!!). I'm going to do, what I do best - guess about the weather!
While the weather has been really weird recently - but nothing really stands out. Above is the surface map around the time of the observation... There's a really odd little LOW right around Pelee - which probably helped get birds up and moving...
BUT
I don't think the weather played major part in the DETECTION of this bird...
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Given the huge number of birders at Point Pelee - and the regular rarity observations - I used to think it was a prime location to study the effects of the weather on bringing vagrant birds to an area. After years of struggling to understand everything - I learned I was WRONG!
Point Pelee - as a geographic feature - is positioned perfectly positioned to capture birds that are moving SOUTH. That's why it see's regular and spectacular concentrations of birds in the FALL... On top of that, as a point - it also concentrates birds from a relatively large area into a space that a single observer could monitor (the tip)... So what does this have to do with the Grace's Warbler? (I said I wasn't going to talk about it)...
Well I would bet at least 3 chicken's that this bird was within 50-100km of Point Pelee yesterday... I'd bet another chicken that it was somewhere NORTH of the tip... Could be inside the park, undetected... Could be Lake St. Clair.. Could be the Bruce Peninsula - but I'd bet those 4 Chickens that it was ALREADY horribly lost, long before it made it's presence known this morning...
Why? It's the primary reason why Point Pelee is a BAD place to study the effects of weather on vagrant birds... The weather today had nothing to do with it's detection (imo).. It just wandered around (potentially moving back south) and the "southbound concentration effect" of the points geography brought it to the tip of Point Pelee.
BAM! What a CRAAZY bird. Very fitting for Point Pelee as well (being a warbler).
Here's a few images from the night/morning:
Above - 850mb winds - not at all interesting...
Below: migration from the night before. Some birds were moving!
Phudge.
Good point about southern overshoots being concentrated at the tip of Point Pelee when reverse-migrating, so overnight weather is less of a factor. However, the tip also gets spectacular groundings of 'normal' spring migrants occasionally - surely due to a combination of suddenly-worsening weather and geography (the Pelee/Lake Erie effect).
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