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Open Mic: Battling Bye-Bye Blackbird – Conserving a Declining Species

At the Mic: Dr. Judith Scarl

Blackbirds are often taken for granted. Red-winged Blackbirds, Common Grackles, and Brown-headed Cowbirds seem omnipresent, singing from the reeds in a marsh, chattering in huge flocks in agricultural fields, or perhaps guarding feeders against smaller, more colorful species.  And then suddenly, and without any fanfare, the Rusty Blackbird largely disappeared from this mix.

By now, the 85-95% Rusty Blackbird population decline, which occurred across just four decades, represents a well documented, but still shocking, phenomenon. The first reports of this massive Rusty Blackbird population crash, published in 1999 by scientists Russ Greenberg and Sam Droege (Conservation Biology, 13(3)), sparked a race to study Rusty Blackbird ecology, understand population threats, and reverse such a dramatic decline.  The International Rusty Blackbird Working Group (IRBWG) was established in 2005 to unite these efforts to understand and conserve Rusty Blackbirds, as well as to identify pressing research and conservation priorities for this vulnerable species.

Photo by Bryan J. Smith

Photo by Bryan J. Smith

Over the last two decades, largely due to diligent research by IRBWG scientists, our understanding of Rusty Blackbird ecology has increased in leaps and bounds, as has our knowledge of the threats Rusty Blackbirds, or “Rusties,” encounter.  Conversion of this species’ wooded wetland wintering habitat to agriculture is likely a primary cause of the decline.  On the breeding grounds, range retractions, wetland drying due to climate change, and high levels of mercury in the eastern portion of the range may also contribute to the Rusties’ reduction in numbers.  Thus, this population crash can’t be attributed to a single “smoking gun”- rather, a combination of factors led to one of the most severe declines ever experienced by a once-common North American landbird.

Despite increased understanding of ecology and conservation issues on the Rusties’ breeding and wintering grounds, Rusty Blackbird migratory ecology remains a mystery.  For long-distance migrants, spring and fall migration are energetically costly and fraught with uncertainty.  Resources are often patchy or unpredictable, predation risk may increase as birds encounter unfamiliar habitats, and changing weather patterns can influence migratory timing. For scientists, bird migration often represents a missing piece of a species’ puzzle, since the great distances traveled over a short period make researching this phase of the life cycle difficult.

At a 2012 meeting in Plymouth, MA, the IRBWG determined that identifying important migratory stopover areas for Rusties was a top priority for the understanding and conservation of this species. In March of 2014, the IRBWG, in partnership with dozens of federal, state, and provincial organizations (link to: http://rustyblackbird.org/outreach/migration-blitz/partners/), launched a three-year Rusty Blackbird Spring Migration Blitz.  The Blitz engages birders across 38 U.S. states, 9 Canadian provinces, and 3 territories to find and report Rusty Blackbirds during their northward migration in order to learn more about habitat use and migratory timing for this species.

Rusty Blackbird Westchester IL 19 April 2014 Christian Goers smaller

Photo by Christian Goers

The Spring Migration Blitz follows on the heels of a highly successful 2009-2011 Rusty Blackbird Winter Blitz, an initiative that challenged birders to seek Rusties during a two-week window in January and February.  In collaboration with the late Russ Greenberg, the champion of the Winter Blitz and the founder of the IRBWG, statistician Brian Evans is using data from the winter Blitz to identify optimal habitat for Rusty Blackbirds along the Mississippi Alluvial Valley, through southern Alabama, and into Georgia, as well as describe habitat features that support large flocks of Rusties, such as the presence of floodplain forests.  Now, the Spring Migration Blitz seeks to identify hotspots where large flocks of Rusties congregate during migration, and our multi-year data collection effort will allow us to evaluate whether migratory stopover areas remain consistent from year to year.  Ultimately, the Spring Migration Blitz represents the first step to ensure that Rusties retain access to high-quality habitat throughout their migratory journey.

During the first year of the Blitz, between 1 March and 15 June 2014, 4750 birders submitted 13,400 checklists reporting Rusty Blackbirds to eBird.  Using these data, we’ve identified 848 “Areas of Interest” based on where large flocks of Rusties congregated in 2014. As a result, in 2015, the Blitz issues two challenges to birders.  First, to assess consistency of habitat use and migratory timing, we ask birders to revisit these Areas of Interest during the Blitz dates for their region. Second, as in 2014, we ask birders to search for Rusties anywhere and everywhere, focusing on Rusty Blackbird habitat. Please report all of your Rusty Blackbird searches under the “Rusty Blackbird Spring Migration Blitz” protocol, available in the “Other” survey category in eBird during the Blitz.  Even if you went birding within Rusty habitat but didn’t find Rusties, we still encourage you to report your effort under the Blitz protocol; this helps us determine whether Rusties are not using a particular area on a given day- or whether no one has looked.

The second season of the Spring Migration Blitz launched on March 1 in 23 southern states, and starting this weekend, birders across all 37 participating states in the continental United States will be joining the Blitz. As Rusties continue their northward journey, six Canadian provinces begin Blitzing on April 1.  Please join us in our quest to understand and support this vulnerable species!

To read more ABA coverage of Rusty Blackbirds, their decline, and the Winter Blitz, please see Paul Hess’s articles in the January/February 2007 and January 2009 issues of Birding magazine, as well as Russ Greenberg’s December 2009 contribution to “Winging It.”

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Dr. Judith Scarl is International Coordinator of the Rusty Blackbird Spring Migration Blitz