Saturday, November 12, 2016

Hypothetical "catch basins" for Great Lakes birding hotspots



Yes, this post was written with the recent Sagebrush Sparrow at Whitefish Point in mind...

Three hypothetical "Catch basins" for Great Lakes birding hotspots...

Legend:

Red = overland migration / concentration (primarily diurnal migration, such as hawks)

Black = overwater migration / concentration (primarily waterbirds like ducks, jaegers, etc)

Purple = overwater concentration (primarily songbirds, shorebirds, etc) - eg,/ birds that find themselves over water but are looking for land...

... I've also tried my best to keep the scale the same - so each figure & basin you're viewing should be comparable to other sites...



Whitefish Point

RED: 

Massive "Catch area" for birds moving in from the southwest. This is where records like Short-tailed Hawk come from... It is also potentially the cause of many mega-rare species that arrive on SOUTHWEST winds (Eg,/ Lucy's Warbler, Hepatic Tanager).... I somewhat suspect that this recent Sagebrush Sparrow didn't "arrive" in the Great Lakes yesterday --- it just finally wandered its way to Whitefish yesterday (this would be a similar process to the Grace's Warbler at Pelee this spring

BLACK:

Whitefish has a massive "catch area" for waterbird movement/migration (hence their awesome counts) - but also vagrants.. This is why they have so many Ancient Murrelet records... 

PURPLE:

For birds passing over water and looking for a place to land (eg,/ Nocturnal migrants) I would guess that there is not an exceptional catch basin... YES - it would be very good given the location of the point related to good migratory weather (eg,/ SW or NW winds) but as we compare with other hotspots, I'd say it's the smallest factor of the three in bringing volume or rarities to Whitefish.






Long Point

RED

The catch basin for diurnal migration isn't massive (imo) for the point... It is possible under specific weather conditions for this to be greatly expanded, but with typical winds/weather I would suggest that the point itself does not benefit from its geography in this way... (eg,/ a wicked west wind would be ideal, SW or N would be average)... 

BLACK

Lake Erie is a great place for waterbirds (volume and rares) but the Long Point catch basin is simply the nearby waters... Specific weather will really help, but the norm is only a degree better than lakewatching would be at any other vantage point on Lake Erie or the Great Lakes in general... 

PURPLE

Boom. Long Point has an exceptional "over water" catch basin - particularly in spring or SW winds in general... Something that hurts its status is the fact that multiple places can receive birds under these conditions, rather than one specific site (eg,/ you can't be at the tip and breakwater at the same time) but it sure helps ratchet up the list... I would bet some benjamins that records at the tip of Long Point such as American Oystercatcher, Varied Bunting and Hooded Oriole were brought in under this effect (over water, looking for a place to land). 




Point Pelee
RED

Pelee is Whitefish Point in reverse (or is Whitefish Pelee in reverse?) in terms of volume-migration and rarities... Pelee catches birds going south... This means awesome hawk migrations in the fall, and re-orienting vagrants in the spring (Grace's Warbler, Carolina Chickadee, Black Swift) The basin could potentially be extended into Michigan to the NW, but it's really quite hard for me (or anyone!) to say if that effect truly takes place... 

BLACK

Similar to Long Point, Pelee likely sees waterbirds from a relatively small area... It just happens to be a bird-magnet type region like the western Lake Erie basin... So you get awesome volume of Bonaparte's Gulls and the occasional/associated Ross's Gull... A notch or two above the Great Lakes norm - but not "out of this world" results... 

PURPLE

I suspect Pelee is hampered by Pelee Island in terms of "catch basin" of birds coming from off the water... They have other options in many directions, so the basin is quite small.. I suspect this is part of the reason why there is no particular concentration of vagrants or migrants from over-water on a regular basis (similar to Long Point and hawk flights, suitable weather is the exception and not the norm)... Yes there was an epic drop of migrants at Pelee this year on May 11th - but there was equally insane numbers at Pelee Island... IF Pelee Island were wiped of the map - would there have been 3x more birds at Pelee??




This is a rapid-fire un-edited post, and part of a bigger idea in terms of what truly makes a birding hotspot enjoyable (and when)... I wanted to get it out of my head - which is how these things end up on the blog... Perhaps more later (or perhaps not)...

Two quick case studies on the same topic before I go:



Caribou Island

RED

Hypothetically there is no effect of this whatsoever. 

BLACK

Hypothetically an average location for waterbird concentrations.

PURPLE

Hypothetically an AMAZING / very large catch basin of things lost over water... Presumably this is what pulled some of the rarities observed here to the island (Clark's Nutcracker, Black-headed Grosbeak, spring Purple Sandpiper)... In theory, spring and fall should be good here (with spring perhaps better)  --- and --- in theory --- the right weather conditions could lead to some truly spectacular fallouts from time to time... 




Netitishi Point

RED/PURPLE combined

Presumably the point-effect is decent, but nothing particularly special when compared to these other sites...

BLACK

The catch basin for waterbirds is off-the-hook... Just a question of A.) being there and B.) actually having them visible due to distance or conditions... 





OK! That's it... 



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