Document ID: chunk:federal_register_of_legislation:F2022L00775:reg:18:p101
Version: federal_register_of_legislation:F2022L00775
Segment Type: reg
Provision Reference: reg 18 (pt 101/152)
Character Range: 318285–321309

(del Hoyo et al. 1996, Higgins and Davies 1996, Snow and Perrins 1998). During this season, it may also feed on emerging insects over lakes, agricultural fields, grasslands and even over semi-desert regions (del Hoyo et al. 1996). On passage the species typically forages over saltpans, coastal lagoons, mudflats, marshes and wet fields, overwintering on estuaries, saltpans, lagoons and saltmarshes, or in more inland sites such as large rivers, lakes, rice-fields, sewage ponds, reservoirs, saltpans and irrigation canals (del Hoyo et al. 1996, Higgins and Davies 1996, Snow and Perrins 1998). It is an opportunistic feeder and is largely insectivorous taking adult and larval terrestrial and aquatic insects as well as spiders, earthworms, small reptiles, frogs, small fish (6-9 cm long) (Richards 1990, del Hoyo et al. 1996).

Population Estimates and Trends
The global population of Gull-billed Tern and Australian Gull-billed Tern combined is estimated to number between 150,000–420,000 individuals (Delany and Scott 2006), but the global population of G. nilotica has not been estimated separately following the taxonomic split. The Australian population estimate and trends are unknown. While recorded observer effort has been inconsistent over the years, there is considerable annual variation in Gull-billed Tern numbers in Victoria, probably with lowest numbers in wet years when there is extensive inland habitat, with more birds coming to Victoria in drought years (Victorian SAC pers. comm. 2020).

Conservation Concerns and Actions
This species has been identified as particularly susceptible to abandonment of breeding sites due to human disturbance (Molina et al. 2014), although early dispersal from breeding sites appears to be a behavioural trait of the species that may mitigate the impact of disturbance. It is possible that, in the future, the effects of climate change could have an adverse impact on food sources and breeding habitat.

Recommended Management Actions
      Quantify the non-breeding population in Australia

      Determine non-breeding areas and migration routes

      Quantify and manage the potential impacts of human disturbance

Wildlife Conservation Plan for Seabirds 137
 Species profiles

 Caspian Tern (Hydroprogne caspia)

 Life History and Distribution
The Caspian Tern (Hydroprogne caspia) is a large gull-like tern with a deep dagger-shaped red bill; it is the largest tern in the world. Its hoarse heron-like croaking call is distinctive. This species has a cosmopolitan but scattered distribution. Their breeding habitat is large lakes and ocean coasts in North America (including the Great Lakes), and locally in Europe (mainly around the Baltic Sea and Black Sea), Asia, Africa, and Australasia. 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