12 
THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 1. March 2012 
TABLE I. Number of color-bandcd Kirtland's 
Warblers from southern Eleuthera. The Bahamas found in 
breeding areas and dates of first observation of males in the 
Lower Peninsula of Michigan. 
Year 
Number found in breeding areas 
First observation 
2005 
8 
7 May 
2006 
12 
4 May 
2007 
23 
5 May 
2008 
14 
4 May 
2009 
16 
3 May 
2010 
7 
2 May 
after the arrival date for most individuals. For 
example, the range of maximum duration of 
migration observed for an additional subset of 
birds, last seen on Eleuthera in mid-to-late April, 
that were found relatively late in the breeding 
season in Michigan, was 27-48 days. We also 
documented that one female, last seen on 27 April 
2006 on Eleuthera and first seen in Michigan on 
24 May 2006. had a maximum migration duration 
of 27 days. Estimating arrival dates of females is 
particularly difficult, even with systematic search¬ 
es. as they do not sing and may escape detection. 
DISCUSSION 
The maximum duration of spring migration for 
male Kirtland's Warblers from Eleuthera (range = 
13-23 days) was shorter than predicted based on 
models developed for thrushes bv Cochran and 
Wikelski (2005), but similar to the 13-14 day 
period for four trans-Gulf spring migrating Wood 
Thrushes ( Hylocichla mu.stelina ) (Stuchbury el al. 
2009). However. Wood Thrushes migrate a longer 
distance of —3,700 km. compared to -2.200 km 
by Kirtland’s Warblers. 
The mean distance traveled/day by male Kin- 
land's Warblers. 144.5 km. was similar to the 
spring migration rate of two female Eurasian 
Hoopoes ( Upupa epops) (122 km/dav and 163 
km/day) between the Sahel of western Africa and 
Switzerland (Baehler et al. 2010) that were 
tracked with geolocators and within the range of 
105-375 km/day traveled during spring migration 
by a Swainson's Thrush ( Catharus ustulaius »that 
w-as studied by radiotelemetry between Illinois 
and Manitoba (Cochran 1987). Daily rates were 
also within the range of estimates for spring 
migration of five Sylvia warbler species to Great 
Britain (range -- 97-232 km/day) and Scandina¬ 
via (range = 98-163 km/day). based on median 
capture and recovery dates in the Mediterranean 
region (Fransson 1995). and for II European 
passerine species on the European (50-260 kin/ 
day ) and desert (120-150 km/day) portions of the 
migration route, estimated from median passage 
rates between Africa and northern Europe (Yo- 
hannes el al. 2009). One individual fall-migrating 
Willow Warbler (Phylloscopus trochilus) traveled 
145 km/day (Hilden and Saurola 1982) and 
another 218 km/day (Hedenstrbm and Peitersson 
TABLE 2. Estimated duration of migration for color-banded male Kirtland’s Warblers from southern Eleuthera, The 
Bahamas to known breeding territory locations in the Lower Peninsula of Michigan. Loeations are given in decimal 
degree coordinates. 
Individual 
Last Bahamas observation 
First Michigan observation 
and location 
and location 
Migration distance (kin) 
Max duration (days) 
Migration rate (km/day) 
1821-91208 
25 Apr 2008 
8 May 2008 
2.199 
13 
169.1 
24.90787 N 
44.4629 N 
76.17171 W 
84.1809 W 
2221-08944 
25 Apr 2008 
9 May 2008 
2.212 
14 
158.0 
24.97589 N 
44.4998 N 
76.15257 W 
83.5794 W 
2131-75811 
25 Apr 2007 
11 May 2007 
2.222 
16 
130.7 
24.90010 N 
44.53544 N 
76.14831 W 
83.53937 W 
2221-08906 
24 Apr 2007 
17 May 2007 
2,211 
23 
96.1 
24.90091 N 
44.58206 N 
2221-08922 
76.15911 W 
84.60934 W 
27 Apr 2007 
24.96263 N 
10 May 2007 
44.46725 N 
2,192 
13 
168.6 
76.17809 W 84.29917 VV 
