NEST DIMENSIONS, BURROW-LINING, AND DECORATION BEHAVIOR OF BURROWING OWLS IN THE PAMPAS

Nesting in burrows is uncommon among birds, but one example of a burrow-nesting raptor is the Burrowing Owl (Athene cunicularia). In most areas of North America, where this raptor has been extensively studied, it typically uses burrows of fossorial mammals, but in southern South America this owl digs its own burrows. We studied characteristics of size, lining, and decoration of Burrowing Owl nests located in dunes, rural areas, and urban areas of the Pampas of Argentina, and analyzed whether such characteristics vary according to land cover. We found that Burrowing Owls construct burrows of similar characteristics in the three habitats sampled, although nests in dunes had wider entrances and longer tunnels. Such variation might relate to the soil, which is more compacted in the dunes than at the rural and urban areas. In both rural and urban areas, owls used manure to line the burrow and decorated the nest entrance with visible objects, but the diversity and amount of materials used for decoration was much higher in urban nests. Our results on burrow measurements, burrow-lining, and decoration behavior of Burrowing Owls in the Pampas were consistent with those reported for North American populations, even though burrow construction processes differ at both ranges of the species' distribution.

Automated summary

Burrowing Owls nest in different habitats with similar characteristics in terms of size, lining, and decoration, although nests in dunes have wider entrances and longer tunnels. In rural and urban areas, owls use manure to line the burrows and decorate the nest entrance with visible objects, but urban nests have a higher diversity and amount of decoration materials. The burrowing behavior and characteristics of Burrowing Owls in the Pampas are consistent with those reported for North American populations, despite differences in burrow construction processes between the two ranges of the species' distribution.