Distribution and number of territorial pairs
Lack of adequate detection probability data limited computation of pair densities since systematic sampling was not adopted. However, the distribution pattern was described. Territorial pairs in the lake mostly occurred in clusters (clumped) in local sites such as Kianjata, Makereka, Kirima and Fuleni (Figure 2). In other parts of the lake, pairs were randomly distributed in a linear manner where the marshes breadth was narrow (100-500 m wide) such as between Ziwani and Kanguu (Figure 2). A total of 103 pairs were mapped during the 2017/2018 breeding season (Figure 2). However, only 61% attempted breeding (i.e. a pair was observed as at least incubating). The highest number of pairs were found in the middle section (52) followed by the southern section (32) while 19 were in the north.
The mean distance between any two neighbouring crane pairs (breeding or territorial) was 302.53±17.02 (SE) m, and a minimum and maximum of 47 m and 759 m respectively. Majority of the pairs’ (n =20) positions were in the range of 201-280 m (Figure 4). These distances were however observed to vary in different clusters of nests in the north, middle and south sections of the lake, and would be expected to vary in different breeding seasons as new pairs take up territories and conditions in the breeding habitat change.