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2011 Season Wrapup

November 19, 2011

By Rafael A. Gálvez

The fall of 2011 was a great season for raptor migration in the Florida Keys. We experienced plenty of renewed enthusiasm about the hawkwatch and excellent flights of migratory birds. Not only did we tally good numbers of several raptor species throughout the traditional Sep 15 through Nov 13 season, but we also experienced great migrations of various birds species, including waterbirds, waders, and passerines.

It is important to keep in mind that although we have often used our daily counts to build enthusiasm about the 2011 hawkwatch, a single season of monitoring tells us relatively little about the status of these birds. As we “celebrate” or “lament” highs and lows, we must keep in mind that FKH 2011’s efforts are only a small part of much larger and continuous endeavor. This season’s data is significant when considered as part of long-term analyses of raptor population trends, such as the RPI (Raptor Population Index) project.

A good season for Northern Harriers or Peregrine Falcons (as was 2011) does not necessarily indicate an increase – or stability – in the populations of these species. Likewise, comparatively low numbers of migrating Ospreys or American Kestrels (as in 2011) are not necessarily indicative of population trends for these species. A minimum of 10 years of count data is recommended in order to draw population trend estimates of relative precision. The Florida Keys raptor migration data may in turn be presented alongside estimates from multiple sites to generate population trends that may serve as indices of the status of North American birds of prey. The RPI currently presents a preliminary analysis that takes into account six years of data from the Florida Keys. Additionally, it has been suggested that raptor migration data begin to achieve higher levels of precision at more than 10 years (Lott 2009).

Considering these factors, the Florida Keys Hawkwatch has made an effort during the 2011 season to continue the standardized methods for daily migration counts as described by Lott (2006) for Curry Hammock State Park, in order to extend the historical data series towards the necessary number of years to generate trend analyses of significant precision.

Please note that although FKH data was entered regularly throughout the 2011 season into the online repository HawkCount, the data as is currently presented in HawkCount for Curry Hammock State Park is still undergoing updates and adjustments, and therefore not yet complete. FKH is working hard to update the site’s historical data, and include totals for all raptor species in HawkCount; currently, only the 8 primary migrants are featured the majority of the years, and data for the remaining species – although collected during migration and in our database – has not yet been entered online. The table above represents totals for 2011 compared to collected data of all raptor species from 1999 through 2011 at FKH.

A full report of the 2011 season will follow soon. Thank you.

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One Comment leave one →
  1. Jeff Bouton permalink
    November 20, 2011 8:46 am

    indeed, high counts are great for the visitors and and wonderful to see for loads of repetition and great practice at identifying raptors. A good day at a hawkwatch site can equate to a lifetime of views of raptors from outside a migration corridor so is an important tool for any birder eager to want to increase their ID skills. This is the immediate return and what every visitor comes to the watch in hopes of seeing. However, as you point out, this is by no means an indication of the health of the populations. It only means you were lucky enough to have more favorable weather conditions than other years perhaps, which brought higher concentrations of migratory raptors over the count site. So much of the migration spectacles we enjoy require the proper topography and the proper weather – in this case mostly wind direction & wind speed.

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