Page 186 - Proceedings of the State Natural History Museum. Issue 37 (Lviv, 2021)

Сharacteristics of visible autumn migrations of the common crane … 185

Visible migrations of waterfowl were analyzed according to observation hours during the
light part of a day, altitude and flight directions. Without knowledge of these peculiarities, it
is not possible to plan and implement measures the management for the protection of
migratory birds. Dynamics of the number of the Common Crane counted for the autumn
passage in 2012-2017 is shown on figure 1.
The autumn migration of this species was observed from the middle of the 1 decade of
st
rd
nd
September to the end of the 2 decade of October, and the main passage lasted from the 3
nd
decade of September to the middle of the 2 decade of October (Fig. 1).
The main influence on the intensity of autumn migration birds had air temperature and
precipitation, less – power and direction of the wind. In particular, the increase in the number
of migratory these birds coincided with a sharp drop in the air temperature below +5ºC mainly
(2012, 2013, 2014 and 2016). Migrating Common Cranes used crosswinds mainly (in
relations to their passage directions), less frequently headwinds and accompanying winds.
Passage of this birds not observed during strong winds (more then 7-8 m/sec) and heavy
rainfall.
Generalized dates of autumn migration of the Common Crane throughout the National
Park for 2009-2020 are given in table 3.
Table 3

Dates of the crane’s autumn passage through the National Park in 2009-2020

Year Date of autumn passage
beginning Ending
2009 - 26.X
2010 08.IX 24.X
2011 10.IX 15.X
2012 04.IX 19.X
2013 12.IX 17.X
2014 12.IX 18.X
2015 10.IX 08.X
2016 07.IX 13.X
2017 11.IX 16.X
2018 - 09.X
2019 - 07.X
2020 - 16.X
Average 09.IX 16.X
Limit 04-12.IX 07-26.X
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