Posts Tagged ‘Roosts’

Purple Martin Roost Rings on Radar

Sunday, August 15th, 2010

Going to your local premigratory roosts are a great way to herald the end of summer. The spectacular swarms of purple martins, descending in on trees, weighing down their branches like a heavy burden as countless more rain down to jockey for a spot  for the night. It is an awe inspiring sight not easily forgotten.

What happens to all those birds in the morning though? Not many people hang around or get up early enough to watch the birds ascend to the sky come sunrise.  The National Weather Service and their Doppler Radars have documented this phenomenon for years since bird movements were discovered on radar back in the 1940’s. On the radar image here, you can see the red arrows pointing to these radar rings (also called doughnuts) formed by the mass of birds flying out and away from the roosting sites. According to the Purple Martin Conservation Association and their Project Martin Roost, more than 300 possible roosts occur in Eastern North America. The largest known roost, at Lake Murray in South Carolina has over 700,000 birds.

Kevin R. Russell and Sidney A. Gauthreaux, jr. did a wonderful study titled, Use of Weather Radar to Characterize Movements of Roosting Purple Martins, (back in 1998) that is an interesting read. You can also read what the National Weather Service has to say about it with their article titled Roosting Birds Detected on NWS Doppler Radar.

If you know of a roost consider visiting one before the martins are gone. You won’t regret it. If you can’t get to one you can always watch our video we took in 2009 of a local roost in Davie Florida here.

Migration is in full swing

Monday, August 25th, 2008

Purple Martin LakeArt:copyright“PurpleMartin Lake”

My martins have been gone for over a month. Reading the posts from the Purple Martin Forums, as far north as Canada, the final martins are heading towards their premigratory roosts. Within a week or two, they will all be gone.

Down south I have noticed some other departures and some new arrivals. The Swallow tailed Kites have all left. They leave shortly after the martins do, also forming premigratory roosts. Though their numbers are far less, their size and beauty makes them no less inspiring and amazing to see. I have begun to notice large flocks of barn swallows feeding silently as they zip back and forth, fairly low to the ground. Their rust colored necks and bellies in varying shades of cream and rust are a dead give away. Around the house, 15 Miles away by the Super Target, and many points in between I see them in groups of 10 to 50 birds. I would guess there must be thousands of these birds spread out all over south Florida in such a fashion. I will have to wait for the first cold snap up north to bring the large flocks of Robins that come every year. I am fortunate to live near a large wetland preserve and there are always large numbers of birds that fly to and from the preserve. Robins always coming and going to the preserve, En Mass. Some other winter time visitors to my yard make illusive appearances such as the pair of Eastern Phoebes that come every winter.

I will shortly begin planning next season in earnest. Another pole, Predator protection, a bat house and more gourds of course. I strive to give my neighbors something to laugh at. If they only knew the joy these birds can bring.