Kentish Plover (Charadrius alexandrinus) and Little Tern (Sternula albifrons) prefer shells for nesting: A field experiment

Shorebird populations are declining worldwide, mainly due to human disturbances and loss of coastal wetlands. However, supratidal habitats as saltpans could play a role in buffering human impact. Saltpans have shown to be important as feeding or breeding sites of some shorebird species. A potential conservation strategy to increase shorebird populations in saltpans is to manipulate the cues that birds use to select optimal breeding habitat. Here it is hypothesized that shorebirds are attracted to bivalve shells due to the advantages they offer. Following this hypothesis, we supplemented a restored saltpan in 2019 and 2021 with bivalve shells, expecting an increase in the number of breeding birds’ nests. More than 75% of Kentish Plover (Charadrius alexandrinus) and Little Tern (Sternula albifrons) nests were found in patches with shells in both years. The best model for both species indicates that the presence of shells is the factor that most correlates with the location of nests. The probability of choosing one place over another to settle their nest increases in areas with an abundance of shells, double in the case of the Kentish Plover and triple in the case of the Little Tern. The result of this study may constitute a valuable tool for attracting birds to restored saltpans and could contribute to the success of expensive restoration projects where time is usually a constraint.