Friday, September 2, 2016

1000+ kingbirds crossing Lake Pontchartrain at South Point

Yesterday I made a quick foray out to South Point in New Orleans East, where the railroad bridge leaves the South Shore headed for Slidell.  This is a great spot for witnessing morning flights of migratory birds.    

I was hoping for a good Eastern Kingbird flight, since that species often stages major movements at this site when we get mornings of northeast winds in early September.  Getting those conditions at this time of year requires some luck, since the cold fronts that produce northerly winds are hard to come by until later in the fall.  However, Tropical Storm Hermine was moving through the eastern Gulf and her cyclonic circulation provided a gentle northeasterly breeze.  Skies were sunny this far from the storm, although a broad bank of clouds off to the east and southeast studded by cumulonimbus tops seemed like it might be a distant view of Hermine's closest edge.

I pulled over at  the base of Highway 11 bridge for brief look, which will usually give an indication of whether a flight is in progress.  Sure enough, within a few minutes, a Blue Grosbeak, a scattering of warblers, and a flock of 80 kingbirds passed overhead and out over the water shadowing  the bridges.  I then headed for the Point, where the flow volume is often greater than at the bridge- though the differences between the two sites are something I am still working out.

On the mile or so hike up to the point, a handful of migrants crossed overhead headed out over the water toward Slidell- including a few Purple Martins.  This species is commonly part of early September movements at South Pt, even after they have departed the New Orleans region otherwise.  I had not seen one elsewhere for weeks.

At the point, a more or less continuous movement was ongoing, with scattered small flocks of warbler-sized songbirds punctuated by larger groups of kingbirds, often 50+.  I took a ten minute count starting at 8:40, and tallied 232 heading out over the water for Slidell, about 70% kingbirds.  For the next ten minutes I just enjoyed the show.  I capped it with another ten minute count at 9:00:  252 birds, again mostly kingbirds.  These indicated a passage rate of about 1450 per hour, about 1000 of them kingbirds.  Since the peak is usually in the first two hours or so after sunrise, and I arrived after that, it may have been stronger earlier.

As usual for this time of year, the second most common participant was Yellow Warbler, but I also was able to pick out a Blackburnian Warbler, and Blue-gray Gnatcatcher, Orchard Oriole, Red-eyed Vireo, Waterthrush sp, American Redstart, Summer Tanager, and Great Crested Flycatcher.  I suppose I could have worked harder at identifying more species, but I am always torn between trying to make identifications and merely putting the binocs down and soaking in the phenomenon.

I then headed back to the Highway 11 bridge, where I had arranged to meet five zoology students from University of Holy Cross, my new academic home.  We counted another 450 birds crossing there in 45 minutes (10:00-10:45), in this case about 90% kingbirds.  

Good stuff!