Bird Time

I love watching birds.  They are colorful and dynamic, meaning they are purrty and constantly changing.  They change colors over the course of the year by molting their feathers, the species that are seen in a particular region change over the course of the year due to migration, and the species that are seen change depending upon what type of habitat you are in.  Like I said, I love watching birds...I like to observe them feeding, fighting, nest building, and flying.  There are very few dull moments when out on the prowl spying on birds.  Optics are optimal for full viewing pleasure, as binoculars or spotting scopes truly enhance the viewing experience.  They are not necessary though; as listening to bird song, counting large migratory movements, or an occasional up close and personal interaction do not require optics. 

September and May are particularly fantastic months to bird watch on Long Island and elswhere in the Northeast.  During September neotropical migrants make their mind blowing voyages from their breeding territories in North America down to Mesoamerica, South America and the Caribbean.  Thus many species that do not call Long Island home during the summer breeding season can be seen during September as they pass through on their way south or in May as they pass through on their way north.  This highly coordinated movement is highly dependent upon the Wind.  The birds pray to the Wind gods, especially Boreas during September.   Boreas gives the migrants a favorable flow to engage on their journey.  In fact the majority of migrants wait for north Winds to blow before they ascend into the air column to move dozens, or hundreds, or thousands of miles to wintering grounds.

This dependency on the Wind can be observed very easily, if one's timing is well planned.  It is not that hard, just wait unit the Wind pushes from a northerly direction during September; particularly if it blows northwest overnight.  Get out into some good habitat early the next morning, and there will likely be a noticeable increase in the abundance and diversity of birds life.  An emerging tool for monitoring these massive movement is through the utilization of NEXRAD Doppler weather radar.  The radars, which are the same units used by NWS and other meteorologists, can detect birds, bats, and insects while they operate in clear air mode.  I think clear air mode is the default mode of operation when significant water laden air masses are not present.  NJ Audubon does a great job of explaining the entire process for using radar to monitor bird migration.  Essentially, many birds are nocturnal migrants, they take to the skies at dusk, and the radars can detect the density, velocity, and direction of birds much as the radars do for nimbus clouds. Birds show up as more pixelated representations on the radar image, denoting many separate individuals as opposed to the more nebulous and contiguous images that result from the relatively larger rain clouds. 

Check out the radar time loop I recorded from the Upton, Ny radar a few nights ago when the Wind was blowing from the north.  Sunset was a little before 7pm and the loop is playing from 6:30ish to 8:00ish.  You can see that small pixelated images emerge on the display just after sunset.  These areas of blue and green represent birds taking to the sky.  They seem to be concentrated over over the Bridgeport area; maybe the migrants piled up as they hit the LI Sound after following the Housatonic River as a flyway.  Maybe a reader can speculate why they are congregating at Bridgeport on this particular evening.

 Here is an image from later that same night.  Lots of birds up and moving.....which way are they headed???

 Looks like they are moving from northeast to the southwest, as would be excepted given the north Wind and the desire to stay over land, which runs generally from NE to SW in this area.  The red signifies birds moving away from the radar and the green shows movement towards the radar. 

The whole NE is lit up with sweet bird action given the favorable Winds and the time of year, September.  The next morning I went out and enjoyed a great day of bird watching.  Here are some possible questions to start up some blog conversation.

How high do you think birds fly during migration?  How do we know theses are birds shown on the radar and not something else, like insects?  Who first though of using radar in this manner?  Please join in.