MANIPULATION AND INVESTIGATION ACTIVITY IN SEA BIRDS: BEHAVIOURAL RESPONSE TO ARTIFICIAL OBJECTS EXPOSED TO THE COLONY
The study was conducted: in 1987-1988 and 2008 on Talan Island (59°20'N, 146°05'E), the Sea of Okhotsk; in 2005 and 2011 on Bear Island (74°23'N, 19°02'E), Svalbard; and in 2009 on Saint Jonah Island (56°24'N, 143°23'E), the Sea of Okhotsk. Sea birds demonstrated interest to some small objects that concerned neither their life nor reproduction. To study this feature in natural conditions, we performed 64 experiments with Crested Auklets (Aethia cristatella), 47 with Little Auks (Alle alle), 15 experiments with other alcids, and one with a representative of Procellariiforms, the Northern Fulmar (Fulmarus glacialis). Birds paid extra attention to small objects that stood out against the natural background. Birds tried to investigate these objects in visual and tactile ways. This feature was more prominent in such highly social seabirds as Little Auks and Crested Auklets. Crested Auklets definitely preferred white or yellow objects. Reactions to orange or green objects were considerable as well. Birds preferred brighter objects even if they were of an unusual colour. Brighter objects stimulated auklet responses to nearby less bright objects. More complicated objects were more preferred than simple ones. Little Auks in the experiments with a full range of colours in similar objects definitely preferred white ones. In the experiments with similar objects of various colours but white, auks first manipulated with the nearest object of any colour. Little Auks tried to touch and manipulate with objects, but paid less attention to their colour and shape than Crested Auklets did. Objects artificially covered with substances with a heavy odour or a spicy taste were not an obstacle to Crested Auklets if they wanted to manipulate with those objects. Little Auks ceased attempts at manipulating with objects smelling menthol.