Reproductive Consequences of Nest Site Selection by Little Terns Breeding on Sandy Beaches

Changes in Vegetation Cover Explain Shifts of Colony Sites by Little Terns (Sternula albifrons) in Coastal Portugal

“…The vegetation cover in the studied colonies is dominated by marram grass (Ammophila spp.) (Medeiros et al 2012), but there are other species such as Cakile maritima, Salsola kali, Elymus farctus, Otanthus maritimus and Euphorbia paralias (Costa 2001).…”

“…Coastal terns, such as the Little Tern (Sternula albifrons), usually breed on sandy beaches with sparse vegetation and are known to actively select locations to place their nests to avoid the most predictable threat, nest flooding by the sea, and the encroachment of vegetation coming from the opposite direction (Fasola and Canova 1991;Medeiros et al 2012). The percentage of vegetation is a very important feature of Little Tern nesting sites, as they prefer to nest in areas with low vegetation cover: less than 30% registered by Medeiros et al (2012) in Ria Formosa, Portugal and an average of 15% recorded by Goutner (1990) in Evros Delta, Greece. For the Ria Formosa birds, Medeiros et al (2012) showed that nest occurrence decreased as vegetation cover increased.…”

“…The percentage of vegetation is a very important feature of Little Tern nesting sites, as they prefer to nest in areas with low vegetation cover: less than 30% registered by Medeiros et al (2012) in Ria Formosa, Portugal and an average of 15% recorded by Goutner (1990) in Evros Delta, Greece. For the Ria Formosa birds, Medeiros et al (2012) showed that nest occurrence decreased as vegetation cover increased. Therefore, Little Terns may adopt a fugitive strategy, moving readily from one site to another (Kotliar and Burger 1986), partly in response to vegetation growth, although other factors such as predation and human disturbance may interact with vegetation cover in a complex way (Gochfeld 1983;Burger 1984, 1986;Medeiros et al 2007Medeiros et al , 2012.…”

“…For the Ria Formosa birds, Medeiros et al (2012) showed that nest occurrence decreased as vegetation cover increased. Therefore, Little Terns may adopt a fugitive strategy, moving readily from one site to another (Kotliar and Burger 1986), partly in response to vegetation growth, although other factors such as predation and human disturbance may interact with vegetation cover in a complex way (Gochfeld 1983;Burger 1984, 1986;Medeiros et al 2007Medeiros et al , 2012.…”

“…On each barrier island of Ria Formosa, the large majority of Little Terns nest close to the inlets (or entrance channels), on areas characterized by the absence of vegetation (or with a small percentage of vegetation cover) and presence of a shell and debris cover (Medeiros et al 2012). Progressively, these areas will be covered with vegetation, which should ultimately lead to the abandonment of those sites (Kotliar and Burger 1986;Medeiros et al 2007).…”