The Diurnal Activity Pattern of the Grey Crowned Crane, Balearica Regulorum Gibbericeps in Mbarara Municipality, Southwestern Uganda

Abstract

The study was conducted from January 2014 to April 2014. It was aimed at investigating the activity pattern of the grey crowned cranes, balearica regulorum gibbericeps. The number of the birds which were seen performing each activity at a particular time of the day beginning from 0700 to 1900 hours were documented. The diurnal activity patterns, habitat preference and association with other animals of the grey crowned cranes were studied in Mbarara municipality, south-western Uganda. The cranes were found in groups of up to 61 individuals. Groups of 3-12 individuals were the most frequently observed. Feeding was the most time consuming activity of the grey crowned cranes and juveniles were found to feed more frequently (31.2%) than the adults (28.8%) and calling was the least frequent daily activity (2.3%) for the adult and 1.9% for the juveniles. Frequencies of observation of feeding, flying, and calling showed two peaks, in early morning and late afternoon. Scanning, preening, and perching followed an inverse pattern, peaking at midday. The feeding habitat and the flock size changed between the morning and the evening. During the morning cranes showed a higher locomotor activity, foraging in smaller flocks and on grounds with higher food availability. On the contrary, during the afternoon, birds showed lower locomotor activity, aggregated in larger flocks, and foraged closer to each other on grounds with lower food availability. I explain these daily changes as a consequence of the risk-sensitive foraging behaviour of the cranes. Agricultural lands were the most occupied habitats by the grey crowned cranes (59%), followed by settlement areas (22%) and river banks were the least occupied habitats (19%). The grey crowned cranes associated more with the marabou storks and least with the sacred ibis. The activities varied according to season. Feeding was particularly more frequent in the wet season than the dry season. I recommend that a further study should be carried out to quantify the damage caused by cranes in the agricultural lands were they feed.