Coastal Waterbird Interim Report

July-September, 2007

In September rainfall finally reached the 25 year mean for the month, all previous months for the year were lower than their means, but the total for the year is still 25% below the yearly mean; how this reflects on birds is anybody's guess. In the last quarterly report I put off any conclusions about nesting this year along the coast that we study but had commented on how poorly the nesting season was going. I could regale you with numbers and graphs to show that the nesting season was one of the lowest ever experienced for coastal birds, except for Least Terns and Black Skimmers but it would be senseless. Even the low nesting does not give the picture; the low number of nests produced almost no young and so the year was basically a washout, with the exception above.

Also reported last time was that a small second wave heron and egret nesting, had started, that fair numbers of White Ibis nests had recently been built on Smokehouse Key and that only time would tell how productive they would be. Three months later there are a scattering of Snowy Egret, Tricolored Heron and Cattle Egret chicks still around the colonies but less than 1% of a normal year. The White Ibis at Smokehouse started deserting nests even before all of the nests had eggs, some produced chicks (25 were the most counted) this would considered failure.

The bright side for nesting was that both Least Terns and Black Skimmers had a successful year, even though the spring high tides moved them around considerably. It is impossible to tell how many young they fledged but the two species had good numbers of big chicks present at the end of the nesting season, therefore had a good year. Also encouraging was the increases in the numbers of coastal waterbirds increasing for the winter. A few examples.

Brown Pelicans; in the study area low since February, jumped up in September and although still lower than the 34yr. mean, it is encouraging to see fair numbers around.

Shorebirds (plovers, sandpipers et. al.); are building up well especially south of Marco; since the north end of the Sand Dollar spit has separated and become a sandbar the numbers have dropped a little, but it is still getting a lot of use.

Laughing Gulls and Sandwich Terns; have both increased to their September highs (last censuses; 1583, 4655 respectively) and put on quite a show at both Sand Dollar and Caxambas Pass.

Rookery Bay Night Roost: There are times when dealing with so many numbers that I am still intrigued; case in point. Last Thursday (9/27) we did the 853rd sundown fly-in census, the birds came in late and it was quite hectic. The next morning after I had taken the data off the tape, I was impressed with the total of 2652 birds on that .3 ha. island. When I checked the data and found that the 31 year mean for September was 2612 just 40 birds less than we recorded, I was impressed. This not only shows how important the roost is but that is needs to be posted.

And the beat goes on.

Theodore H. Below

Avian Ecologist