SHORT COMMUNICATIONS 
401 
The Wilson Journal of Ornithology 123(2):401-403, 2011 
Conspecific Egg Destruction by a Female Cerulean Warbler 
Than J. Boves, u David A. Buehler , 1 and N. Emily Boves 2 
ABSTRACT.—Conspecific egg destruction is an 
adaptive behavior that has typically evolved in multi- 
brooded, polygynous, or colonial avian species, and can 
be difficult to observe. We describe the first case of egg 
destruction in the Parulidae, which consists of mostly 
'ingle-brooded and socially monogamous species. In 
this case, a female Cerulean Warbler {Dendroiea 
cerutea) destroyed 5-day old eggs at a conspecifie's 
nest This act was likely committed to secure a breeding 
opportunity with a high quality male or to decrease local 
competition for resources. There is also the possibility 
this behavior may have been pathological and not 
adaptive. Received 15 September 2010. Accepted 14 
December 2010. 
Destruction of eggs by conspecific adults has 
been documented in many avian species (e.g.. 
Pieman and Belles-Isles 1987. Brown and Brown 
1988, Hannsen et al. 1997). Conspecific egg 
destruction is generally considered adaptive and 
may occur when individuals are attempting to: (I) 
gain breeding opportunities with eonspecifies that 
were previously mated to others (a sexual 
strategy), (2) gain resources through cannibalism 
(an exploitation strategy). (3) decrease competi¬ 
tion for local resources (e.g., food or nest sites), or 
(4) manipulate the number or gender of offspring 
(only applicable when parents are responsible for 
the egg destruction) (Hrdy and Hausfater 1984). 
Egg destruction by birds occurs mainly in 
polygynous, colonial, or cooperatively-breeding 
species where the behavior is usually explained in 
a sexual or limited resource context. Great Reed 
Warblers (Acrocephalus anmdinaceus ) (Hannsen 
et al. 1997). House Wrens ( Troglodytes aedort) 
• Quinn and Holroyd 1989). Green-rumped Parrot- 
lets ( Forpus pasterinus) (Bonebrake and Bes- 
singer 2010), and Marsh Wrens [Cistothorus 
paliistris) (Pieman and Belles-Isles 1987) are 
among those species where individuals have been 
observed destroying, or have been inferred to have 
destroyed, conspecific eggs. Additionally, lypi- 
1 Department of Forestry. Wildlife, and E-isheries. 
University of Tennessee, Knoxville. IN 37996. USA. 
(jams Nature Center. Knoxville, TN 37920. USA. 
‘Corresponding author: e-mail:tboves@utk.edu 
cally monogamous, solitary members of Troglo- 
dytidae and Mimidae have been documented 
engaging in heterospecific egg-destroying behav¬ 
ior (Belles-Isles and Pieman 1986). 
The Parulidae consists of mostly monogamous, 
single-brooded species lhat construct their own 
nests (Perrins 2004). These life history traits do 
not seem appropriate for evolution of conspecific 
egg destruction behavior because it appears best- 
suited for species that have high potential for 
breeding opportunities with multiple mates (e.g.. 
Great Reed Warblers) or have limited availability 
of nest sites (e.g., House Wrens). We found no 
documentation of egg destruction by members of 
Parulidae in the literature. Cerulean Warblers 
(Dendroiea ceruled) are insectivorous Nearctic- 
neotropical migratory members of Parulidae. 
Female Cerulean Warblers build cup-shaped nests 
in the canopy of deciduous forests of the eastern 
United States (Hamel 2000). We describe a case 
of conspecific egg destruction by a Cerulean 
Warbler and discuss the potential significance of 
this behavior. 
METHODS 
This event occurred in the North Cumberland 
Wildlife Management Area in Campbell County, 
Tennessee. USA (36 ’ 21 ' 23.5" N, 84 18' 08.4" W). 
This area is at an elevation of ~900 m and consists 
predominantly of mixed mesophytic forest with 
oak (Quercus spp.), maple (Acer spp.). hickory 
(Carya spp.), and tulip poplars (Uriodendron 
ttdipifera) as the dominant tree species. We 
estimated, through intensive spot-mapping and 
nest-searching throughout the breeding season, 
Cerulean Warbler territory density at 1,3 pairs/ha 
on the 10-ha forest stand where the nest was 
located. This density is slightly above average in 
this part of the Cumberland Mountains (TJB, 
unpubl. data). The forest stand was occupied by a 
high proportion of young males (second-year 
birds). We captured and banded 23 male Cerulean 
Warblers in this stand from 2007 to 2010, 43% of 
which were second-year birds: across the rest of 
the Cumberland Mountains, only 28% of captures 
were second-year males (TJB, unpubl. data). 
