Inter-speciﬁc variation in avian responses to human
Blackwell Publishing, Ltd.
DANIEL T. BLUMSTEIN,* ESTEBAN FERNÁNDEZ-JURICIC,†
PATRICK A. ZOLLNER‡ and SUSAN C. GARITY*
*Department of Ecology, and Evolutionary Biology, 621 Charles E. Young Drive South, University of California,
Los Angeles, CA 90095–1606, USA; †Department ofBiological Sciences, California State University Long Beach,
Peterson Hall 1–109, 1250 Bellﬂower Blvd, Long Beach, CA 90840, USA; and ‡USDA Forest Service North Central
Research Station, Forestry Sciences Laboratory, 5985 Hwy K, Rhinelander, WI 54501, USA
1. Increasing urbanization and recreational activities around and within biodiversity
hotspots require an understanding of how toreduce the impacts of human disturbance
on more than a single species; however, we lack a general framework to study multiple
species. One approach is to expand on knowledge about the theory of anti-predator
behaviour to understand and predict how different species might respond to humans.
2. We reviewed the literature and found that only 21% of studies that used a behavioural
approach tostudy human disturbance focused on multiple species. These studies identiﬁed
a number of potential predictive variables.
3. We developed a simulation model that investigates interspeciﬁc variation in different
parameters of disturbance with variation in human visitation. We found that ﬁtness-related
responses, such as the quantity of food consumed by a species, are relatively sensitive to
thedistance at which animals detect humans, the frequency of disturbance by humans
and the interaction of these factors, but are less sensitive to other characteristics.
4. We examined avian alert distance (the distance animals ﬁrst orientated to an approaching
threat, a proxy for detection distance) across 150 species, controlling for phylogenetic effects.
We found that larger species had greateralert distances than smaller species, which
could increase local spatial and temporal limitations on suitable habitat with increasing
5. Synthesis and applications. Our results suggest that body size could be a potential
predictor of responses to human disturbance across species, and could be used by managers
to make conservation decisions regarding levels of humanvisitation to a protected site. We
suggest that three things are essential to develop predictive models of how different species
will respond to human disturbance. First, multiple indicators of disturbance should be studied
to select those with lower intraspeciﬁc variation for a given study system. Secondly, the
species-speciﬁc nature of responses should be identiﬁed. Thirdly, life history, naturalhistory
and other correlates with these species-speciﬁc responses must be assessed.
Key-words: alert distance, conservation behaviour, detection distance, ecotourism,
ﬂight initiation distance, recreation
Journal of Applied Ecology (2005) 42, 943–953
Animals are increasingly affected by urbanization
processes that modify different aspectsof their biology
© 2005 British
Correspondence: Daniel T. Blumstein, Department of Ecology,
and Evolutionary Biology, 621 Charles E. Young Drive South,
University of California, Los Angeles, CA 90095 –1606, USA
(fax + 1310 2063987; e-mail firstname.lastname@example.org).
(Wearing & Neil 1999; Marzluff, Bowman & Donnelly
2001). This is likely to worsen because the rate of
humanvisitation to the world’s biodiversity hotspots
is expected to double by 2020 (Christ et al. 2003).
However, our ability to predict the effects of humans
on wildlife is restricted (Hill et al. 1997; Gill, Norris
& Sutherland 2001). We need to develop conservation strategies that protect multiple species (Taft
et al. 2002; Heikkinen et al. 2004). Limitations may
D. T. Blumstein