Spanish Sparrow (Passer hispaniolensis) Science Article 1
[…]. The study was carried out in May and June 2000 in Castro Verde, Southern Portugal (37 deg 41?N, 08 deg 03?W). The Castro Verde region is a cereal crop steppe, alternating with fallow grounds, which are usually grazed by sheep and cattle. The sparrows nest in the small Eucalyptus spp. plantations and olive groves that abound in the area. Diet samples were obtained using the ligature method, which consists in applying a constricting band around the neck of nestlings with sufficient pressure on the proventriculous to prevent them from swallowing food items brought to the nest by the parents, but loose enough to avoid strangling (Kluijver, 1933). […].
Marques, P. M., Boeiro, M., Canario, F. & Vicente, L., Ardeola 50(1), 2003, 71-75