Migration routes and chronology of American black ducks
Date
2013
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Migration influences the ecology, evolution, and conservation of
migratory animals (Webster et al. 2002), yet migration routes and timing
between breeding and wintering areas is virtually unknown for American
black ducks Anas rubripes. We used satellite telemetry to identify migration
routes and stopovers, estimate migration chronology, and describe variation
among black ducks marked between 2007–2009 in Delaware, New Jersey,
New York, Ohio, and Virginia. A total of 31 transmitters provided at least
one full data set during spring migrations. Black ducks departed wintering
areas March 18–June 7 ( x̅ = April 17), averaged 3.35 stopovers (SE = 0.3
stopovers; range = 1–5 stopovers) and 6.44 d at stopovers (SE = 0.8 d; range
= 0.54–12.2 d), migrated 1,126 km (SE = 89.5 km; range = 270–1,396 km),
and arrived at inferred nesting areas April 16–June 28 ( x̅ = May 9). South
Atlantic Flyway black ducks migrated almost twice as far and took nearly
twice as many stopovers as Mississippi and North Atlantic Flyway black
ducks; South and North Atlantic Flyway black ducks arrived at inferred
nesting areas approximately 2 and 4 weeks after those from the Mississippi
Flyway, respectively. Black ducks south of the 40th parallel migrated more
than 50% farther, took nearly twice as many stopovers, and arrived at inferred nesting areas 2 weeks after those to the north. Black ducks east of the 76th
meridian migrated nearly 25% farther and arrived at inferred nesting areas 3
weeks after those to the west. Nine black ducks spent all or portions of spring
migration along the Atlantic Coast, and 10 used the Hudson and St. Lawrence
River valleys. Stopovers included Long Island Sound, NY, Narragansett Bay,
RI, Lake Champlain, VT, Merrymeeting Bay, ME, and the Gulf of St.
Lawrence, Canada. All 11 black ducks wintering in Ohio stopped at Lake St.
Clair, Saginaw Bay, St. Mary’s River, or the Georgian Bay. A total of 13
transmitters provided at least partial data during autumn migrations. Black
ducks departed inferred nesting or molting areas October 5–December 1 ( x̅ =
October 24), averaged 2.0 stopovers (SE = 0.3 stopovers; range = 1–4
stopovers) and spent 12.6 d at stopovers (SE = 3.5 d; range = 0.25–41 d),
migrated 993 km (SE = 202.9 km; range = 277–1,485 km), and arrived at
wintering areas November 18–December 18 ( x̅ = December 1). Our study
confirms the importance of known stopovers and emphasizes the continued
need for conservation and management of wetland habitats along established
migration corridors. Furthermore, migration chronology and stopover
duration of stay from our study should be incorporated into energetic carrying
capacity models to better inform and direct habitat goals for black ducks in
northeastern North America.