Gowda et aL • TERRITORIAL FIDELITY OF THE PURPLE-THROATED CARIB 
85 
the non -H. caribaea flowering season suggest 
they may be aiding their spatial memory by main¬ 
lining site-fidelity even when heliconias arc not 
in Hotter. On a broader level, many migratory 
North American hummingbird species have been 
a-capiured at the same general locations between 
successive years (Bassett and Cubie 2009), and 
vitne lekking hummingbird species return to the 
sime leks between years (Stiles and Woll 1979). 
Long-term spatial memory may be a general 
characteristic of hummingbirds, although it may 
have evolved through a variety of different con¬ 
texts (feeding, migration, and mating). 
Our observation of strong fidelity to Helicon ia 
patches by Purple-throated Caribs has implica¬ 
tions for coevolution between hummingbirds and 
Hcliconia. Bill morphology, body size, and 
energetics of male and female Purple-throated 
< aribs arc closely related to one or the other 
species of Heliconia on the islands of St. Lucia 
and Dominica (H. caribaea with males: H. bihai 
with females; Temeles et al. 2000, Tcmeles and 
Kress 2003). Close correspondence between 
hummingbirds and flowers suggests these islands 
^ 'hotspots’ (Thompson 2005) of reciprocal 
evolution. Thompson (2005) noted that gene flow 
amon g populations can dilute and weaken recip- 
10031 adaptation. However, year-to-year fidelity 
"• territorial male Purple-throated Caribs to the 
'•'me patches of heliconias combined with territo- 
"Ol exclusion of intruding conspecifics and hetero- 
•c-ecifics would reduce gene flow in both plants and 
hummingbirds, resulting in strong coevolution of 
^Tic-throated Caribs with //. caribaea through 
toiprocal selection for flower numbers and male 
tod fighting ability (Temeles and Kress 
Similar fidelity by traplining females may 
‘^-'contribute to strong ecological interactions and 
1 duuonary interactions with II bihai through 
flower size and shape and bill morphology 
'Temeles et al. 2009). Benkman et al. (2003) 
sported a case of coevolutionary interactions 
fvttteen a non-migratory population ot Red 
Cr, Abil| s [Loxia cunirosira) and lodgcpole pine 
lp ' n “s contorta spp. latifolia) where reciprocal 
■election has largely shaped their bill morphology 
^ ^rd defenses, respectively. 
Our observations indicate that male Puiple- 
'hroated Caribs continue to associate with patches 
caribaea even when these plants are not in 
This raises the questions of whether males 
*** defending and exhibiting fidelity to the 
Hcliconia species, or to the sites in which these 
plant species occur. We suggest it may be both and 
have no doubt that heliconias arc the resource 
magnet that attracts hummingbirds to these sites. 
Our contention is supported by the observation that 
with the exception of introduced plants (e.g., 
bananas, citrus, and some ornamentals): we have 
found no native plant species on these islands that 
are as rewarding as heliconias in terms ol overall 
nectar production (flowers of these heliconias 
produce 60 to 300 pi per day: Gowda and Kress 
2008). Thus, fidelity to a long-lived, highly- 
rewarding resource, even when it is not in flower, 
may be a viable territorial strategy, especially if 
alternative low-quality resources are locally avail¬ 
able. Once a territory is abandoned, it may be 
energetically more costly to re-establish it than to 
maintain it during times of low flower availability. 
acknowledgments 
Wo thank the Minisiry ot Agriculture and the Environ¬ 
ment; Forestry. Wildlife, and Patks Division; Common¬ 
wealth of Dominica. Government of St. Christopher and 
Nevis, and Forestry Department. Ministry of Agriculture 
and Fisheries, St. Vincent and the Grenadines tor 
facilitating this study. We also thank Arlington James. Enc 
11\polite. Ida Lopez. Anne Jno Baptiste, and Gregory 
Pereira for logistic help and discussion. Wc thank C. E. 
Braun and two anonymous reviewers lor helpful comments 
and assistance on this manuscript. This work was supported 
by a Weiniraub Graduate Fellowship from the Department 
of Biological Sciences. The George Washington Univers.ty 
to VG and also by the Cosmos Club. Sigma-Xi. and the 
Smithsonian Institution, Field work for ibis study was 
supported by grants from National Science Foundation 
(DEB-06142IS) to E. J. Temeles and W, J. Kress. 
LITERATURE CITED 
Armstrong. D. 1992. Conelation between nectar supply 
and aggression in territorial honeyealers: causation or 
coincidence? Behavioral Ecology and Sociobiology 
30:95-102. 
Armstrong. D. A.. C. L. Gass, and G. D. Sutherland 
1987. Should foragers remember where they ve been. 
Explorations of a simulation model based on the 
behaviour and energetics of territorial hummingbirds. 
Puses 563-586 W Foraging behaviour (A. C. Kamil. 
J. R. Krebs, and H. R. Pulliam. Editors). Plenum Press. 
New York, USA. 
Baloa. R. P. and A. C. Kamil. 1989. A comparative study 
of cache recovery by three corvid species. Animal 
Behavior 38:486-495. 
Bassett. F. and D. Cubie. 2009. Wintering hummingbirds 
in Alabama and Florida; species diversity, sex and age 
ratios, and site fideliiy. JoumaJ of Field Ornithology 
80:154-162. 
Benkman. C. W„ T. L. Parchman. A. Fa vis. and A. M. 
Siepielski. 2003. Reciprocal selection causes a 
