Report

FKH 2011  Fall Season Totals and Summary

By Rafael A. Gálvez

A total of 19,685 raptors were counted this season from the Florida Keys, including vultures. Counters at the site made the first effort in documenting vultures since 1999 and 2000, and compared to those seasons, 2011 was the highest count. Compared to all other seasons, this year’s total excluding vultures was 18,484 and a new maximum for the project, surpassing the average of 14,104.

High counts for many species were surpassed this season at the Florida Keys, including Northern Harrier, Broad-winged Hawk, Swainson’s Hawk, Red-shouldered Hawk, Short-tailed Hawk and Peregrine Falcon. Additionally, the highest day count in project history was tallied this season, totaling 3423 raptors on October 11. No other count before had exceeded 3000. Of 11 species tallied that day, 45% consisted of Sharp-shinned Hawks, 26% Broad-winged Hawks, and included 267 Peregrine Falcons and 238 Northern Harriers.

Despite some below-average results for species like American Kestrel and Merlin, the results for all species this season were an improvement over 2010’s totals. That season had been challenged by an absence of organization and funding starting 2009, affecting the length of its count period.

The Florida Keys Hawkwatch is located in Curry Hammock State Park in the Middle Keys, not far from the city of Marathon. Fall raptor counts have been done at the park since 1999, typically starting September 15 and running into mid November. Counts are conducted from an elevated structure alongside the eastern shoreline of Little Crawl Key, at one of the narrowest points of land on the island chain.

This year marked the first season the project was organized and staffed at the local level, and funded primarily by a group of regional supporters. The efforts towards reestablishing this project finally showed their results after a lengthy period of restructuring. For 2011, project officials made an increased effort at incorporating interpretive signage at the site and in engaging the public in an assortment of educational workshops, including banding demonstrations. More visitors and participants were recorded this year at the hawkwatch than ever before.

A total of 18 raptor species have been documented from the Florida Keys since the project’s inception, of which 17 were reported this year. Originally, a focus was placed on the passage of falcons, primarily Peregrines, although all raptor species were documented. However, after the 2000 count, vultures were ignored because of their uncertain passage up and down the Keys, and the effort they took from monitoring other species. During that count, out of 11,932 Turkey Vulture observations from the site, only 3,720 were recorded as southbound, illustrating the complexity of the issue.

Black Vultures are an uncommon sight in the Florida Keys, and they average at less than one a year. Turkey Vultures on the other hand arrive throughout the fall in large loose streams, with the Keys as their potential destination. Hawkwatch visitors during October get to see many vultures in the vicinity, and grow excited about migration. Yet their numbers don’t come anywhere close to those observed in Texas, Mexico and Panama. With slight restructuring of project protocols, and help from a team of trained volunteers, the official counters were able to include Turkey Vultures as part of the count again during 2011. The species is certainly among those using the Keys flyway each fall, and its past exclusion has created an incomplete picture of migration in the region.

Ospreys totaled at 1034, a good recovery from the previous season’s disappointing low of 444, and the 960 of 2008. It was the best season for the species since 2007 although it fell slightly below the 1073 average, and well below the site’s all time high of 1652. The species is a breeder within the site’s vicinity, and at least a couple of pairs remain in the area year round, making counts at times confusing. Additionally, the Middle Keys and adjacent Florida Bay in particular are common winter destinations for many Ospreys, further confusing the movement of individuals during fall. However, three-digit day flights for the species, once regular during migration, have not been documented since 2007. The peak flight during 2011 was 64 on October 11.

Although kites use the Keys in substantial numbers during migration, the hawkwatch has traditionally started too late in the fall to document the bulk of their passage. Monitoring would have to begin as early as the second week of July to catch Swallow-tailed Kite migration. With the start date of September 15, a total of 18 were tallied this season, above the 13 average. Mississippi Kites were tallied at a total of 48, well above the 24 average.

Northern Harriers had their best season this year with a total of 1065, surpassing the previous high of 835 from 2007. The species often flew earlier in the day or later in the afternoon, sometimes at very high altitudes and undeterred by rain. On several occasions it was observed migrating far out over the water in disassociation with the island chain, as if having had covered Florida Bay and briefly crossed over the keys to fly directly over the ocean towards Cuba.

Broad-winged Hawks had their best season this year with a total of 5831, surpassing the previous maximum of 5237 from 2003. The best flight was October 10 with 1363. The species has been increasing every year after hitting a low of 2727 in 2006.

Both Accipiter species did substantially better than average. It was the third highest season for Sharp-shinned Hawks at 3800, above the 2833 average. October 20 was the largest day flight for the species in project history with 1525. This was following days of thunderstorms when no Sharp-shinned Hawks flew. Between 13:00 and 14:00 that day, 560 were counted. Groups of up to thirty simultaneous individuals were observed in migrating clusters. Many birds were seen well offshore, following the coastline.

However, it was the season for Peregrine Falcons at the Florida Keys. With 2976, the species surpassed the highest season count in U.S. history of 2858 established also in the Keys in 2003. The best day was October 2, with 393. Numerous Peregrines were often seen in kettles with other species, or flying far offshore. At times, they seemed to altogether bypass the Keys landmass and engaged in direct open water flight towards the Caribbean.

Unfortunately, the other two falcon species were once again tallied below their averages, yet did significantly better than their 2010 totals. American Kestrels have not been documented above 2500 since 2002, and this year’s 2101 was the best total since 2007. Merlins tell a similar story, with numbers varying significantly between seasons. This year’s total of 468 was an improvement over the all time low of 176 from 2010. However, Merlins have been tallied as high as 834 in 1991 and 661 as recently as 2007.

For a full report of the 2011 season, contact Rafael Gálvez at TASpublisher@gmail.com.
Look of a full Gulf-Caribbean Flyway report in the Hawk Migration Studies Journal, Volume 38, No. 1.