Monday, June 26, 2017

Brown Booby on the Causeway Bridge

Today as I was driving southbound on the Causeway at 7:25 PM, I was treated to a Brown Booby at mile marker 16.3.  It was just off the bridge, and turned in such a way as to approach the side just as we passed.

This is the exact spot where a roost of this species has been located for the last few years.  Birders crossing the bridge had been seeing small numbers occasionally, but it wasn't until a boat trip in June 2015 that allowed better viewing of the bridge structure that we discovered that there were many more there than suspected.  The peak count I know of was of 37 on one boat visit last October.   To my knowledge, there have not been any recent boat trips- a similarly large number could still be roosting on the bridge there every day.

How crazy- this species was an extreme rarity in Louisiana waters up until a few years ago.  Then they inexplicably started appearing with greater frequency- including on near-coastal lakes and even once flying with geese over the rice country!  This tropical species has been turning up in other parts of the country- and even Canada- with increased frequency at the same time as this has been happening in our own state.  These odd appearances out of range and out of habitat together pose one of the most fascinating and enigmatic ornithological mysteries I have ever heard of, and I have yet to hear an explanation that is even remotely convincing.

So the next time you cross the Causeway, keep alert!  These birds can turn up anywhere along it, but are most likely to be seen near mile marker 16.3 on the west side.  When roosting, they are invisible from the roadway- thousands of cars pass these rare birds every day, completely unaware of their presence!

Good birding, Peter

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