108 Wigeon vigilance on golf courses
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 105–114
and fairways. Human activity was recorded
within 50 m and 100 m radii surrounding the
focal flock, selected because previous
studies have shown wigeon respond to
human disturbances within 100 m in natural
habitats (Mori
et al.
2001; Bregnballe
et al.
2009). Distances were estimated visually, but
were assumed to be accurate because golf
course fairways had known distance markers
(
i.e.
yardage markers) which provided a
benchmark for measuring distance from the
birds. To obtain data throughout the range
of human activity levels, recordings were
conducted opportunistically at varying times
and days of the week to encompass low
(week-day) and high (week-end) levels of
human activity.
Non-parametric analyses were used
because vigilance data were not normally
distributed (Shapiro-Wilk normality test:
W
= 0.798,
P
< 0.01) and could not be
normalised by transformation. Wilcoxon
signed-rank tests were used to compare the
percentage of time spent vigilant when
humans were absent and present, and also
to test for sex differences in vigilance
behaviour. Kruskal-Wallis analysis of
variance was used to test the effects on
vigilance of human activity levels and
distance from water. The relationship
between vigilance and flock size was tested
using the Spearman rank correlation. All
analyses were made using Programme R
2.13.1 (R Development Core Team 2011)
with significance set at
P
= 0.05 and data are
presented as means ± standard error (s.e.).
Results
A total of 174 focal bird recordings were
conducted on American Wigeon grazing on
golf course fairways. There was a high rate
of human activity in the study area,
averaging 54 (± 4.4) people present per
hour, and 1.86 (± 0.2, range = 1–10) people
recorded per focal bird observation. Overall,
the percentage of time spent vigilant
averaged 6.8% (± 0.50,
n
= 174), which is
below vigilance rates previously reported for
wigeon in more natural habitats (Table 1).
Mean flock size was 60.8 (± 1.40, range =
20–100) individuals.
Individual vigilance behaviour did not
differ during periods of human presence or
absence within 50 m (
W
125
= 2026,
P
= 0.86,
n.s., Fig. 1a) or 100 m (
W
172
= 3794,
P
= 0.67, n.s., Fig. 1b) of the focal flock, nor
did vigilance differ during different levels of
human activity (50 m:
H
4
= 2.47,
P
= 0.48;
100 m:
H
4
= 1.43,
P
= 0.70; n.s. in both
cases; Fig. 1b). Males were more vigilant
than females when humans were present
(
W
101
= 1692,
P
< 0.01, Fig. 2a), whereas
vigilance levels for the two sexes did not
differ in the absence of human activity
(
W
69
= 697,
P
= 0.31, n.s., Fig. 2b). Vigilance
levels increased markedly as individuals
foraged at progressively greater distances
from water (
H
3
= 14.68,
P
< 0.01, Fig. 3a)
and in larger flocks (
r
172
= 0.15,
P
= 0.04,
Fig. 3b).
Discussion
Contrary to previous research documenting
adverse behavioural responses of waterfowl
to disturbance by humans in natural areas,
this study did not find any evidence for
human activity affecting the vigilance
behaviour of American Wigeon feeding in a
highly human-impacted environment.
Rather, vigilance rates corresponded to
