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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 
It is uncertain whether the Blue Jay mortality 
was due to starvation, hypothermia, antagonistic 
interactions, or a combination of these factors. 
Blue mussels (Mytilus edulis) and pieces of fish, 
possibly from a species of clupeid, were also 
inside the traps. We did not see the jays 
consuming these items, but believe this lobster 
bait likely attracted them to the traps. 
DISCUSSION 
Little consideration is given to the influence of 
inactive fishing gear on survival of terrestrial 
organisms, such as passerine birds. Conversely, 
the effects of derelict fishing gear on marine 
organisms are well documented (Dayton et al. 
1995). We did not find literature addressing 
capture and subsequent mortality of terrestrial 
birds in idle fishing gear. This lack of acknowl¬ 
edgment is perhaps surprising since devices 
similar to traditional lobster traps have been used 
to capture landbirds lor decades (Weaver and 
Kadlec 1970). Information concerning the preva¬ 
lence of this phenomenon and its potential effect 
on terrestrial bird populations would be valuable 
to avian conservation efforts. 
More than 3 million lobster trap tags were issued 
in the State ot Maine in 2009 (Maine Department of 
Marine Resources 2010). This figure accounts for 
the number of traps currently authorized to harvest 
lobsters in Maine, but certainly underestimates the 
total number of traps present in the state, most 
notably unused traps. If even a small fraction of 
lobster traps are stored in a way that attracts, 
captures, and kills terrestrial birds, the resulting 
mortality could influence local bird populations. 
This is likely the first documentation of 
cannibalism by Blue Jays in addition to the 
conservation implications of our observations. 
Reports of filial cannibalism exist for the family 
Corvidae (Richter 1965, Baida and Bateman 
1976). However, a search of the ornithological 
literature yielded no evidence of adult-adult Blue 
Jay cannibalism and only one record in which 
adult corvids consumed the flesh of another 
conspecific adult ( Andersen 2004). 
This observed behavior of Blue Jays ingesting 
the tissue of adult conspecifics was probably the 
product of a high-stress situation. The observed 
birds were previously wild and became captive 
Confined in traps without food, the Blue Jays 
faced both starvation and social stress. Given this 
context of captivity and our observations of the 
emaciated live birds, the motivation for intraspe¬ 
cific predation appears to be, mainly, nutritional. 
Wild-caught birds held in captivity in previous 
reports of cannibalism in non-corvids were 
provided food and water ad libitum. Social 
stresses (e.g., high densities, lack of necessary 
stimuli) were cited as causes of cannibalism in 
these cases (Rodenburg and Koene 2007). The 
social stress of captivity may have had a role in 
inducing the Blue Jays we observed to cannibal¬ 
ize, but we believe, based on the poor body 
condition of the birds, nutritional stress was a 
major reason for cannibalism. 
We argue that improper storage of lobster traps 
and other fishing gear poses a serious risk to 
certain local passerine species, especially during 
periods of low food availability. Simple and 
inexpensive solutions exist to minimize bird 
capture, stressed behavior (e.g., cannibalism), 
and mortality in inactive fishing traps. Thorough 
removal of bait would prevent luring of birds to 
stored traps. Elimination of residual bait is 
especially important if trap storage occurs during 
periods when food for terrestrial birds is limited. 
During times of low food availability, birds are 
more likely to seek out new or additional food 
sources. Method of storage could also be used to 
discourage Blue Jays and other species from 
entering idle traps. Fishing traps stored indoors 
will not attract birds. Entrance funnels of traps 
stored outdoors should be obstructed, thus pre¬ 
venting unintended capture of terrestrial birds. 
Traps could also be covered (e.g., with a 
tarpaulin) to further protect against inadvertent 
trapping. These simple precautions would mini¬ 
mize capture of birds and situations of extreme 
nutritional stress in which birds may exhibit 
cannibalistic behavior, and would aid in conser¬ 
vation of local bird populations. 
ACKNOWLEDGMENTS 
We thank two anonymous reviewers. We also thank W. 
Donald Hudson Jr. for organizing the Christmas Bird Count 
for Brunswick, Maine and Brittany B. Cline for encourag¬ 
ing preparation of this manuscript. 
literature cited 
Andersen, E. M. 2004. Intraspecific predation among 
Northwestern Crows. Wilson Bulletin 116:180-181. 
Balda, R. P. and G. C. Bateman. 1976. Cannibalism in 
the Pinyon Jay. Condor 78:562-564. 
Dayton, P. k., S. F. Thrush, M. T. Agardy, and R. J- 
Hofman. 1995. Environmental effects of marine 
fishing. Aquatic Conservation: Marine and Freshwater 
Ecosystems 5:205-232. 
