The Wilson Journal of Ornithology 124 ( 1 ): 113 — 118 , 2012 
NEST SURVIVAL, PHENOLOGY, AND NEST-SITE 
CHARACTERISTICS OF COMMON NIGHTHAWKS IN A NEW JERSEY 
PINE BARRENS GRASSLAND 
MICHAEL C. ALLEN 1 AND KIMBERLY A. PETERS 12 
.ABSTRACT—We monitored Common Nighthawk (Chordeilcs minor) nests in a managed grassland in the New Jersey 
Pine Barrens in 2009 and 2010. and assessed habitat selection by comparing vegetation characteristics at nests with random 
locations. We found relatively high nest survival with an estimated 79% chance of survival through incubation da. y 
survival rate = 0.987, n = 16 nests); predation was the most common cause of failure (n — 2). Movements o >oun t up o 
45m from the original nest site) were frequent, which introduced uncertainty that prevented us bom estimating surviva 
through Hedging. Nest sites had significantly more open ground cover (e.g.. sand, lichen) than random sites, as we as ess 
shrub and grass cover, shallower Utter, and lower mean vegetation height. Received 9 May Jill. Aciepit - ugus 
The breeding biology and demography of the 
nightjars (Caprimulgidae) has been poorly studied 
worldwide relative to other groups (Straight and 
Cooper 2000, Holyoak 2001. Cink 2002, Brigham 
et a h 2011). The Common Nighthawk (Chorde ties 
minor) is the most widely distributed and best- 
studied North American nightjar with a breeding 
range extending from Yukon, Canada to Panama 
(Brigham et al. 2011), but published data on 
reproductive rates, habitat preferences, and nest¬ 
ing phenology are lacking. Nesting usually occurs 
on the ground in a variety of open habitats including 
grasslands, gravel rooftops, and disturbed or open 
forests (Fowle 1946. Dexter 1952, Kantrud and 
Higgins 1992). The species is still common in many 
;i, eas. but has exhibited a negative long-term 
population decline in the United States (Nebel 
eta h 2010, Sauer et al. 2011 ), and has been assessed 
«‘threatened’ in Canada (COSEWIC 2007). and of 
conservation concern in several U.S. states (e.g., 
New Jersey; NJENSP 2008). 
Only two published studies to our knowledge 
l|av 'e quantitatively examined nest survival rates 
ot Common Nighthawks (Kantrud and Higgins 
'"2, Perkins and Vickery 2007), of which only 
0ne used modern techniques involving daily 
survival rates (Perkins and Vickery 2007). Sim- 
llar Y rnost data on reproduction by this species 
arc from urban rooftop nest sites (Bowles 1921: 
Sutton and Spencer 1949; Dexter 1952. 1956; 
Weller 1958; Dexter 1961; Armstrong 1965; 
Gramza 1967) with relatively few from natural 
' New Jersey Audubon Society. Cape May Bird Obser- 
v; »°ry. 600 Route 47 North. Cape May Court House, NJ 
98210. USA. 
Corresponding author; 
e *mail; kpeters@massaudubon.org 
settings (Fowle 1946. Rust 1947, Kantrud and 
Higgins 1992. Perkins and Vickery 2007. Lohnes 
2010). The only quantitative data on vegetation 
characteristics at nests in natural settings are from 
Kantrud and Higgins (1992) and Lohnes (2010). 
Data on reproductive rates, timing of nesting 
activities, and habitat preferences are important 
prerequisites to effect conservation actions for 
any species; these arc especially lacking tor the 
Common Nighthawk. 
We report data from Common Nighthawk nest 
monitoring in 2009 and 2010 in managed 
grasslands in the Pine Barrens of southern New 
Jersey. Our objectives were to: (.1) assess nest 
survival ami predation rates lor comparison with 
previous studies, ( 2 ) quantity nest-site character¬ 
istics and test whether they differed from those 
of surrounding available habitat, and (3) present 
location-specific information on clutch size, 
behavior of young, and phenology of nesting 
activities. 
METHODS 
Study Area.— Fieldwork was conducted on 
the - 3,000-ha Lakehurst section of Joint Base 
McGuire-Dix-Lakehurst in New Jersey, USA (40 
q-> ' jq 74 ^ 22' W) within the boundaries ot the 
Pinelands National Reserve. Approximately 
520 ha of the site are actively maintained as 
grasslands by mowing, burning, and mechanical 
shrub removal. All management activities at the 
site occur during winter or early spring which 
minimized disturbance to breeding grassland 
birds. Grasslands at the site occur in three main 
areas embedded within a landscape dominated by 
pitch pine (Pinus rigida) and oak (Quercus spp.) 
forests. These are: (1) Test Sile-a 170-ha area 
surrounding a 3.5-km long runway that is rarely 
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