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.