Document ID: chunk:federal_register_of_legislation:F2022L00775:reg:18:p102
Version: federal_register_of_legislation:F2022L00775
Segment Type: reg
Provision Reference: reg 18 (pt 102/152)
Character Range: 321052–323997

North American birds migrate to southern coasts, the West Indies and northernmost South America. European and Asian birds winter in the tropics. African and Australasian birds are resident or disperse over short distances (del Hoyo et al. 1996).
The species shows a preference for nesting on sandy, shell-strewn or shingle beaches, sand-dunes, flat rock-surfaces, sheltered reefs or islands with sparse vegetation and flat or gently sloping margins surrounded by clear, shallow, undisturbed waters (Flint et al. 1984, Higgins and Davies 1996, del Hoyo et al. 1996, Snow and Perrins 1998). The species nests in large colonies or as single pairs or small groups amidst colonies of other species, neighbouring nests placed between 0.7 and 4 m apart (del Hoyo et al. 1996). The species may forage up to 60 km from the site of the breeding colony (del Hoyo et al. 1996). It also forms winter roosts on sandbars, mudflats and banks of shell (del Hoyo et al. 1996). Its diet consists predominantly of fish and minor amounts of the eggs and young of other birds, carrion, aquatic invertebrates (e.g. crayfish), flying insects and earthworms (Flint et al. 1984, Urban et al. 1986, del Hoyo et al. 1996, Shuford and Craig 2002).

 Population Estimates and Trends
The global population is estimated to number between 250,000–470,000 individuals (Wetlands International 2015). The overall population trend is increasing, although some populations are decreasing, stable, or have unknown trends (Delany & Scott 2006). This species has undergone a large and statistically significant increase over the last 40 years in North America (266 per cent increase over 40 years, equating to a 38.3 per cent increase per decade; Butcher and Niven 2007). Australian population estimates and trends are unknown.

Species profiles

 Conservation Concerns and Actions
Human disturbance represents a threat to this species. Caspian Tern colonies are especially vulnerable to disturbance during the early courtship and incubation stages, during which human visitation results in the flushing of the whole colony, potentially leading to nest or colony abandonment (Cuthbert and Wires 1999; Shuford and Craig 2002). The effect of disturbance during research activities has been well quantified, with activities such as banding and cannon-netting representing a large proportion of the reproductive failure in colonies studied (Shuford and Craig 2002). Disturbance due to recreational activities are less well quantified but likely also significant (Shuford and Craig 2002). Much of the loss of reproductive success due to human disturbance occurs through gull predation of chicks during the few seconds of panic flight in which the eggs and chicks of a nest are left exposed (Shuford and Craig 2002). Historically, exploitation has resulted in large population decreases through the collection of eggs and adults for food and feathers (Shuford