Pseudo-egg “fabrication” by Grey-headed Albatrosses Thalassarche chrysostoma on Marion Island

Abstract

Pseudo-eggs are foreign objects, resembling eggs, found inside the nests of birds (Conover 1985) and have been recorded in several ground-nesting seabirds (Coulter 1980; Conover 1985; Mellink 2002; DeStefano et al. 2013; Wagner et al. 2013; Witteveen et al. 2015). They are more common among species that have larger clutches or multiple brood patches (Coulter 1980; Wagner et al. 2013) where pseudo-eggs are included to increase their clutch size (Coulter 1980; Conover 1985; Wagner et al. 2013; Witteveen et al. 2015). Albatrosses and petrels however, only lay one egg; rare two-egg clutches result from two females laying in the same nest, with one of them being an inexperienced breeder (Ryan et al. 2007). The occurrence of pseudo-eggs has only been reported for Laysan (Phoebastria immutabilis) and Black-footed Albatrosses (P. nigripes; Bartholomew & Howell 1964; Grant 1982). We did not find any record of albatrosses breeding in the Southern Ocean that exhibited pseudo-eggs.