Wednesday, September 7, 2011

A good kite year

This is obviously a good kite year here in Veracruz, Mexico. At September 5, the 2011 Veracruz River of Raptors count had already logged 266,166 Mississippi Kites and 213 Swallow-tailed Kites, with both species still coming through in some numbers. Especially Mississippi Kites are expected to continue for some time in the order of thousands a day, usually trailing off to hundreds a day by late September. They still pass through in October, but in very small numbers.

Looking at counts from 2002-2011 (, we see that this year we've already surpassed the seasonal totals for Mississippi Kite of 2003, 2004, 2005, 2006, 2008 and 2009. We will likely exceed last year's count (274,621), and have a real chance at breaking the exceptional 2002 record of 306,274 Mississippi Kites. The mean number of Mississippi Kites recorded at the two Veracruz count sites combined for the period 1995-2004 was 157,199 (Ruelas Inzunza 2007). The species' recent expansion of its breeding area has been well-documented by excited northeastern birders, and that expansion is reflected in the higher recent counts in central Veracruz, where virtually the entire world population is believed to pass through a relatively small area each fall.

We're also seeing more Swallow-tailed Kites this year than were recorded on average for the period 1995-2004, but we are still far away from the exceptional 2007 seasonal total, when a new record was set with 563 Swallow-tailed Kites. The  average number of STKI for the period 2002-2010 is 275, a number we seem to be on track for this year.

For other raptors it is of course still way too early to say anything about trends. We have had an unusual number of Zone-tailed Hawks already, but this and many other species normally peak late September / early October, when we will have a much better idea about how this year's numbers fit into the larger trend line.

Cited literature: 
Ruelas Inzunza, E. (2007) Raptor and wading bird migration in Veracruz, Mexico: spatial and temporal dynamics, flight performance, and monitoring applications - Dissertation University of Missouri - Columbia.

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