SHORT COMMUNICATIONS 
817 
TABLE 2. Wilson’s Plover nest-habitat and nest-scrape descriptions. Values reported in habitat adjacent to the nest are 
ihe mean percentages for each site. Values reported in nest-scrape content are the percentage of nests per location that 
contained the content. Percentages were estimated to the nearest 5%. 
Habitat adjacent ti 
i nest 
Nest scra| 
pe contents 
Welland 
Percent live 
vegetation 
Percent dead 
vegetation Percent rock 
Percent bare 
ground 
Shells 
VegetaUon 
Rock 
Bare ground 
Orient 
35 
2 
14 
49 
46 
40 
60 
100 
Grand Etans 
44 
11 
6 
39 
40 
60 
60 
100 
Galiion 
27 
6 
5 
62 
40 
60 
20 
100 
Etane Poisson 
25 
0 
0 
75 
100 
66 
0 
100 
Grand Case 
15 
10 
10 
65 
100 
100 
100 
100 
Simpson Bay Lagoon 
0 
0 
0 
100 
0 
0 
100 
100 
generally initiated earlier than those that were 
unsuccessful (successful: n = 13, mean date = 17 
Mar: unsuccessful: n = 22, mean date = 29 Apr). 
Apparent nest success was higher in the earlier 
pan of the nesting season when 75% of nests 
initiated prior to the mean laying date (28 Feb-13 
Apr; n = 16 attempts) were successful. Nests 
initiated after the mean laying date (14 Apr-23 
Jun; n = 19 attempts) had an apparent nest 
success of 5%. 
We documented the probable cause of failure 
for 13 of the 22 nests that failed through 
identification of tracks leading to and away from 
the nest scrape. Ten nests were predated by feral 
dogs {Canis lupus familiaris) and three nests were 
crushed by vehicles. We could not identify the 
cause of failure for nine nests. Seven of the nine 
nests were predicted to hatch near the period of 
our nest check, and failure could have been with 
either the eggs or the chicks. The eggs in two of 
the failed nests disappeared well before the 
predicted hatching date, suggesting egg predation. 
Wilson's Plover nests were on the shorelines of 
saltwater ponds surrounded by mangroves. All 
wetlands with plover colonics were within 250 m 
of small towns or housing establishments (mean 
distance = 106.09 ± 0.248 m). All nests were on 
flat ground within 0.25 m of pond elevation level. 
The sediment at all nest locations was fine-sized 
light-colored sand. Nest scrapes included a mix of 
shells, vegetation, rocks, and bare ground (Ta¬ 
ble 2). We observed shells in 48.6% of nests, 
vegetation in 51.4% of nests, rock in 51.4% of 
n ests. and bare ground in 100% ol nest scrapes. 
The mean distance between nests within colonies 
with multiple nests, was 14.7 m (n = 23; range = 
10—19 m). 
We used the percentage at each nest ot the lour 
habitat parameters (live vegetation, dead vegeta¬ 
tion/woody debris, rock, and bare ground) record¬ 
ed within a 2-m radius of the nest center to 
calculate mean nest habitat. The mean nest habitat 
was 52% bare ground. 34% live vegetation, 9% 
rock, and 5% dead vegetation/woody debris 
(Table 2). Five nests were surrounded by 100% 
bare ground, including three that successfully 
Hedged chicks. 
DISCUSSION 
Apparent nest success of Wilson’s Plovers on 
St. Martin was similar to that reported in the 
United States. Causes for nest failure on St. 
Martin were comparable to those reported at other 
breeding sites, mainly mammalian predation and 
human disturbance. 
Introduced predators were a common threat to 
breeding Wilson’s Plovers on St. Martin. Dogs 
were often observed near one of the breeding sites 
beginning in late May. near the time of a potential 
peak in chick hatching. Dogs were not observed 
eating eggs or chicks, but dog tracks were 
identified approaching and leaving nest scrapes 
during nest checks when eggs were initially 
observed missing. Predation by rats (black [ Rattus 
raft us] and Norway [R- norvegicus] ) and Indian 
mongoose ( Herpestcs javaniais ), which are pres¬ 
ent and common on St. Martin (Brown 2008). 
may explain failure of nine additional plover nests 
where shell fragments were found near nests. 
Human disturbance was also identified as a 
cause of nest failure on St. Martin. All locations 
where Wilson's Plovers bred on St. Martin were 
within 250 m of housing developments. Vehicles 
were often observed driving to and from devel¬ 
opments across wetlands and subsequently drove 
over and crushed eggs in three different plover 
nests. Repeated disturbance bv vehicles traveling 
through the nesting colony may have caused adult 
