The Wilson Journal of Ornithology 124(2): 345-353, 2012 
BIRDS CAUGHT IN SPIDER WEBS: A SYNTHESIS OF PATTERNS 
DANIEL M. BROOKS 1 
ABSTRACT.—Results of queries through public avian list-servers and a thorough literature search formed a data base to 
synthesize patterns of birds trapped in spider webs. Sixty-nine cases of birds, representing 54 species in 23 families, were 
reported trapped in webs. Hummingbirds were the most diverse family (9 species) and had the most cases of entrapment (n 
= 20). Archilochus coluhris represented the species with the most cases of entrapment (n = 6). Mean mass and wing chord 
length of all species trapped were 11 g and 61 mm. respectively, Eighty-seven percent of all individuals had mass ^15 g 
and 88 fr had a wing chord <90 mm. Phaelhornis longucmareits and Mellisuga minima represented the smallest species 
(mass = 2 g. wing chord 1 37 mm), and Streptopelia sencgalcnsis was the largest (mass = 80 g, wing chord = 138 mm). 
Thirty cases of birds were entrapped without human intervention: 22 died and eight not wrapped in silk freed themselves. 
Those wrapped in silk invariably died unless freed by a human observer. One-half of all reported spider webs were ot the 
genus Nephila. and all were orb weavers except for a single Lutrodecius. Ncphila rlavipes entrapped nine species 
representing 14 cases, ranging from Mellisuga minima (mass 2 g. wing chord = 37 mm) to Lathams ustulatus (mass = 
23 g. wing chord = 93 mm). Patterns, causes, and consequences of birds entrapped in spider webs arc discussed, including 
orb weavers as opportunistic predators of birds trapped in webs, and spider webs as a natural environmental hazard to birds. 
Received 31 August 2011. Accepted 7 December 2011. 
Birds have a wide variety of predators. Top 
ptedators to birds include humans, who have a 
long history of harvesting birds for sport, protein, 
and ritual (Brooks 1999). Other predators of birds 
include fish (Lockwood 1922), reptiles (Dove et 
af 2011), amphibians (Norris-Llye 1944), mam¬ 
mals (Bisbal 1986), and a variety of avian species 
ntnging from raptors (Mayr 1966) to certain 
passerines (Graves 1978). Hymenoptcrans (Grant 
1959), odonates (Hofslund 1977), and mantids 
(Carignan 1988) have also been reported to attack 
birds, especially smaller species such as hum¬ 
mingbirds (Trochilidae). 
Other cases involving invertebrates include 
birds trapped in webs of orb weaver spiders, of 
which there are numerous accounts in regional 
journals (e.g., Coale 1912, Lockwood 1922, 
Kirkham 1925. Abbot 1931. Bent 1953. Grant 
• 959, Morris 1963, Doberski 1973. Pratt 1974, 
Vernon 1976. Hofslund 1977, Donnelly 1980, 
Dean 1984. Gosling 1984. Levy 1987. Carignan 
1988. McKenzie 1991. Shaw 1994. Cheke and 
Mann 2001, Heck and Heck 2001, Riddell 2001. 
Engel 2006. Cox and Nesmith 2007, Peloso and de 
Sousa 2007, Brooks et al. 2008). The pattern of 
birds trapped in spider webs has not been properly 
synthesized to date despite extensive documenta¬ 
tion because these observations are largely consid¬ 
ered incidental and often dismissed by scientists as 
unremarkable (Graham 1997 ). For example, Lima 
(1993) broadly synthesized patterns of predator 
'Houston Museum of Natural Science, Department of 
Vertebrate Zoology. 5555 Hermann Park Drive, Houston, 
TX 77030, USA; e-mail: dbrooks@hmns.org 
escape by North American birds but did not include 
fates of birds trapped in spider webs. Miller and 
Gass (1985) examined patterns of predation of 
hummingbirds and concluded the majority of the 
incidents were unusual and inconsistent. All cases 
they examined were of vertebrate predators except 
one, and that single case was not a spider. 
Two colleagues and I found a web-entrapped 
Swainson's Thrush (Catharus ustulatus) in Sep¬ 
tember 2007 while inspecting damage to wildlife 
sanctuaries on High Island (Galveston County, 
Texas, USA) following Hurricane Humberto 
(Brooks et al. 2008). Subsequent literalure review 
revealed a plethora of short published and 
unpublished reports of birds entrapped in spider 
webs with extensive variation in species and their 
respective fates. The objective of this synthesis is 
to examine patterns and fates of birds trapped in 
spider webs. This topic warrants investigation 
because birds trapped in spider webs have been 
reported in the literalure on multiple occasions 
and may represent more than a series of trivial 
incidents. Even the most detailed reports to date 
(e.g.. Graham 1997, Cox and Nesmith 2007, 
Peloso and de Sousa 2007, Sakai 2007) only 
examined a single or limited number of cases and 
lacked a thorough synthesis of multiple cases. 
METHODS 
Data were obtained from an exhaustive litera¬ 
ture search and replies to queries to several avian 
list-servers (NEOORN-L. ORNITH-L, African- 
Birding-L) on 17 September 2007. Some recipi¬ 
ents of the initial posting forwarded the message 
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