Friday, September 30, 2011

Bird Funnels

There are places on earth that just have the perfect combination of geographical features and habitat that make them exponentially more birdy than other places and we appropriately call them "Hotspots".  Many of them, like Magee Marsh, OHHigh Island, TX, and Fort Jefferson on the Dry Tortugas are legendary hotspots during migration.  

A birder's local patch may not have the volume and intensity of those internationally known hotspots, but over time we come to know our birding haunts intimately and appreciate the subtleties of bird patterns and movement within them.  Within my own lunch-hour birding patch (and within all my former patches) I have come to discover that there are certain locations that are much more consistently birdy than others...micro-hotspots if you will.  Even though the terrain and habitat appear to be equal, some spots simply have more birds than others.  Recently, I've been pondering "Why?"

My conclusion is that there naturally exist "bird funnels" - places where birds coming from wide and far are narrowed into a concentrated smaller area for we birders to enjoy.  A bird funnel, especially on the micro level may be different than a known fly-way or even than an island of habitat in which birds abound.  These bird funnels may occur for a variety of reasons and the theory I think applies to both the mega-world-hotspots as well as the micro-hotspots within our local patches.

Allow me to use my lunch-hour birding patch as an example.  Below are satellite images of both the north and south portions of my patch.  I have indicated the consistently birdiest sections in orange.  The yellow lines show the perceived funneling that I am talking about.  At the tip of each funnel is where I see the most birds on a regular basis, no matter the season.

My Lunch-hour birding patch - north of 4000 S.  

The larger funnel is created by a ridge that runs along its eastern side below those apartment buildings.  The wide end of the funnel where some orange micro-hotspots are indicated is a natural landing pad as birds following the Jordan River cross the road and then typically funnel into the point.  At the point, are three russian olive trees not immediately connected to the larger chain of cottonwood trees.  It always amazes me how many different species I have found, sometimes at the same time, in those three little trees. 

The smaller funnel shown on the top of the satellite image may in reality be an extension of the larger funnel, rather than its own little funnel.  It is sort of a hopping off place as birds decide whether to forage here a bit more or cross the river.  These funnel areas shown above are dense with trees and brush, but not unlike the areas in the river bends to the west.  Those groves of trees in the river bends hardly ever have any birds.  That twenty foot high ridge seems to be the main factor creating the bird funnel.
My Lunch-hour birding patch - south of 4000 S.

In the southern portion of my lunch-hour birding patch, the river and the golf course combine to create a spectacular bird funnel.  I may not see a single bird in the rest of this area, but right at the funnel point I hit the jackpot every time.

So, dear readers, taking a look at your own micro-hotspots within your local patch, does the bird funnel theory hold true?

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