1/31/2024 0 Comments Blue shoebill stork![]() During the breeding season (June-October), adults performed shorter movements (on average 1.1 km per day) but increased the daily distances towards the end of the breeding period and start of the rainy season (average of 10.5 km per day in December). The daily distances moved varied throughout the year, particularly for adult birds. Although the home range size was similar between adults and immatures, there was large individual variation (range 95% kernel for immatures: 233-2628 km 2, range 95% kernel for adults 304-3375 km 2). We found that Shoebills in the Bangweulu Wetlands were largely sedentary, moving less than 3 km for 80% of days. To understand how movements changed throughout the year, we calculated the mean daily distances per month, for each individual and for each age group. To answer this question, we calculated the distance Shoebills moved per day and estimated their annual home range areas using Kernel Density Estimations. The dashed line indicates the border of the Bangweulu Wetlands Game Management Area. ![]() For this study, we only considered the movements of immature (2-3 year old) and adult birds (> 3 year old), as first year juveniles remained near the nest for a long period after fledging.įigure 1 Cumulative 95% and 50% kernel density estimations for all tracked (A) immature and (B) adult Shoebills, and cumulative 50% kernel density estimation for each (C) immature and (D) adult individual, based on the GPS tracking periods indicated in Table 1. ![]() Shoebills were tracked for up to 5 years, during which 6 individuals provided more than 1 year of data, maturing from juveniles to immatures, and 4 immatures provided more than 3 years of data, becoming adults. To understand the movement and distribution of Shoebills, we deployed GPS devices on 11 Shoebills (10 juveniles and 1 adult) between 20 in the Bangweulu Wetlands, Zambia. We do not know, for example, if there is any connection between different Shoebill populations, important for genetic exchange. Despite being an extremely charismatic species with its pre-historic looks, the movement ecology of Shoebills was until now completely unknown, which is unsurprising given the remoteness of their habitat and the small number of Shoebills ringed in the past. This species is categorised as Vulnerable by IUCN, with populations declining due to habitat degradation and loss, illegal bird trade and disturbance by humans. ![]() Shoebills inhabit permanent swampy wetlands with seasonal flooded grasslands, where they prey on fish in shallow waters or use floating vegetation as fishing sites (Guillet 1978, Mullers & Amar 2015). The Shoebill ( Balaeniceps rex) is an iconic wetland specialist, with a patchy distribution in central-eastern Africa, from South Sudan to Zambia. Acácio, M., Mullers, R.H.E., Franco, A.M.A., Willems, F.J. Changes in surface water drive the movements of Shoebills. ![]()
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