108Wildlife Conservation Plan for Seabirds

108 Wildlife Conservation Plan for Seabirds

Principal threats to Little Penguins are introduced predators, bycatch, habitat loss through coastal development, oil pollution, mortality through roadkill and collisions with watercraft, and human disturbance at breeding colonies (Stevenson and Woehler 2007; Chiaradia 2013, Dann 2013, Cannell et al. 2016). Additionally, the impact of changing oceanic conditions appears to impact food availability and reproductive success (Voice et al. 2006, Wu et al. 2012). Introduced predators impact colonies throughout the range to varying extents, with substantial mortality occurring particularly from domestic dogs (Canis familiaris) but impacts were also noted from pigs (Sus scrofa), cats (Felis catus) and Weka (Gallirallus australis) in New Zealand. Invasive grasses and weeds are another threat as they can inhibit access to breeding sites as well as cause the loss of breeding sites. The species is assessed as being moderately at risk from bycatch in gillnets, although qualitative data are lacking (Crawford et al. 2017). As such, recreational gillnets in some parts of the range appear to have the potential to cause considerable mortality (Stevenson and Woehler 2007; Crawford et al. 2017).

An additional challenge for this species is in the fast-changing marine and terrestrial environment, particularly the rapidly warming sea of southern Australia (Voice et al. 2006, Wu et al. 2012). In southwestern Australia, the sea surface temperatures have been associated with poorer breeding including lower fledging success, fewer chicks per pair and a lower mean mass of chicks at fledging (Cannell et al. 2012). Little Penguins have been also shown to catch fewer prey in warmer conditions (Carroll et al. 2016). Oceanographic change may lead to a mismatch between plankton and the small pelagic fish that are also penguin prey (Hinder et al. 2013). Increasing terrestrial temperatures are also responsible for Little Penguin mortality due to hyperthermia (Cannell et al. 2011, Chambers et al 2013).

 Control, or eradicate invasive species at breeding colonies

 Implement best practice quarantine measures at breeding colonies to reduce the risk of any invasive species (re)establishing on islands

Wildlife Conservation Plan for Seabirds 109

Lesser Frigatebird (Fregata ariel)

TABLE Species information for the Lesser Frigatebird (Fregata ariel)

The Lesser Frigatebird (Fregata ariel) is the smallest frigatebird with black and white marking that vary with age and sex. The species has a typical frigatebird structure with long pointed wings, long bill with hooked tip and a very long, deeply forked tail. Lesser Frigatebirds are found throughout tropical waters in the Indian, west and central Pacific Oceans. The Lesser Frigatebird breeds on small, remote tropical and sub-tropical islands, in mangroves or bushes, and even on bare ground. Outside the breeding season it is sedentary, with immature and non-breeding individuals dispersing throughout tropical seas, especially of the Indian and Pacific Oceans (del Hoyo et al. 1992). It feeds mainly on fish (especially flying-fish) and squid, but also on seabird eggs and chicks, carrion and fish scraps (del Hoyo et al. 1992).