Page 184 - Proceedings of the State Natural History Museum. Issue 37 (Lviv, 2021)

Сharacteristics of visible autumn migrations of the common crane … 183

Table 1
Number of the Common Crane counted during visible autumn migrations
near the Svalovychi village in 2012-2017

Year
Indexes Total
2012 2013 2014 2015 2016 2017
Individuals 285 330 403 632 227 860 2737
Birds in flocks 285 330 403 632 223 859 2732
Single birds - - - - 4 1 5

The distribution of the number of birds in flocks during visible autumn migrations in
2012-2017 is shown in table 2.
Table 2
Distribution of the number of іndіvіduals in Common Crane’s flocks
on autumn passage in 2012-2017

Flock sіze (number of flocks / birds), % Total of Average
flocks / number of
Year
2-25 26-50 51-75 76-100 >100 birds in birds in the
flocks flock, (limit)
78,6 7,1 14,3 14 20,4±6,41
2012 - -
36,8 15,1 48,1 285 (3-70)
58,4 33,3 8,3 12 27,5±9,20
2013 - -
29,4 34,2 36,4 330 (4-120)
41,7 33,3 16,7 8,3 12 33,6±8,44
2014 -
12,2 33,5 30,5 23,8 403 (4-96)
28,6 14,3 14,3 42,8 7 90,3±28,74
2015 -
7,6 7,4 12,7 72,3 632 (23-222)
66,7 16,6 16,6 6 37,2±19,17
2016 - -
23,8 23,3 52,9 223 (3-118)
52,6 12,9 5,3 21,0 5,3 19 45,2±10,54
2017
15,2 12,9 8,5 44,8 18,6 859 (2-160)
55,7 18,6 7,1 10,0 8,6 70 39,0±5,12
Total
17,7 16,4 14,1 20,5 31,3 2732 (2-222)

As can be seen from table 2, the most frequent migratory birds of this species in 2012-
2017 were observed in small flocks – 2-25 individuals (on average 55,7% of all registered
flocks), but the number of birds in them was significant (on average 17,7% of all counted
birds). The largest number of birds was observed in large flocks – more than 75 individuals
(on average 51,8% of all counted birds), but the number of such flocks was a small percentage