Diurnal feeding strategies of the Ferruginous Duck (Aythya nyroca) in Lake Tonga (Northeastern Algeria)

Abstract

Although the Ferruginous Duck (Aythya nyroca) has thoroughly been studied, the foraging behaviour of this species is still not completely known. In the present paper we studied the diurnal feeding behaviour of ducks. We monitored the annual cycle of birds through two fieldtrips per month. The instantaneous behaviour of birds was recorded in regular 30-minute intervals from 7 a.m. to 4:30 p.m., amounting a total of 456 observation hours. Food searching activity corresponds to a quarter of the total diurnal time budget of the Ferruginous Duck. Foraging behaviour was classified into five categories dominated by the “diving”, which is almost 45.61% of the total search time. Foraging activities at the water surface considered to be secondary activities, including feeding by “bill”, “neck and head”, and “beak and head” in a rate of 19.86%, 14.53%, and 13.98%, respectively. The “toggle” remains a minor activity and represents only 5.99% of foraging time. The feeding behaviour of this species correlated to several environmental parameters (rainfall, temperature and wind velocity), and linked to the group size of ducks visiting the lake. Regarding the food intensity, our results show the highest values for “bill and head” behaviour. “Diving” has the longest feeding interval (16.16±14.1 minutes), while foraging by “bill” has the shortest (0.69 ± 0.48 minutes).

Diurnal time-activity budget and foraging techniques of red-crested pochards (Netta rufina) wintering at the wetlands of West Bengal, India

“…In the present study, resting, including sleeping inthe RCPs,was the dominant activity during the entire wintering period. Diurnal resting and other comfort activities represented a way for rearrangement of energy reserves in wintering populations of Anatidae (Tamisier and Dehorter 1999;Draidi et al, 2019). In the present study, swimmingwas the next prevalent activity.…”

“…Ali et al (2016) reported that the proportion of time allocated for sleeping ranged between 40% and 75% in white-headed duck, ferruginous duck, Eurasian teal, common pochard, and tufted duck. Das et al (2011) and Draidi et al (2019) also reported similar diurnal activity patterns in fulvous whistling duck and ferruginous duck, respectively. In the present study, resting, including sleeping inthe RCPs,was the dominant activity during the entire wintering period.…”

“…Diurnal variations in the feeding time were prominent during the study period. Marked diel fluctuations in the time-activity budgets were also reported for white-headed duck, shelduck, and fulvous whistling teal (Green et al, 1998b;Boulekhssaim et al, 2006;Das et al, 2011;Draidi et al, 2019). Khan et al (1998) studied selected activities of nonbreeding common pochards at Sarp Lake, Turkey, and recorded a negative correlation between foraging and swimming, resting and swimming, and swimming and preening.…”

“…Migrants of the EAFF must forage when 1) replenishing at a stop-over site after a long over-Himalayas flight, 2) molting, and 3) accumulating fat in preparation for long migration crossing the Himalayas towards their breeding sites. The distribution of time in different activities in the day time, including foraging, varies among waterbird species and individuals (Draidi et al, 2019). Time allocations for different daily activities surely have important implications for meeting the energy requirements of the concerned species.…”

“…Amat (1984) compared the habitat use of RCPs and common pochards in winter and spring. The timeactivity budgets of common pochards (Green, 1998a;Ali et al, 2016) and ferruginous ducks (Sabir, 2004;Draidi et al, 2019) have been studied. Although the time-activity budgets of several other wetland ducks (Green et al, 1998a;Das et al, 2011;Ali et al, 2016;Saker et al, 2016) and shorebirds (Morrier and McNeil, 1991;Marteinson et al, 2015) are on record, such studies on RCPs are altogether absent.…”