Title: The status and dynamics of populations of the Great Bustard (Otis tarda) and the Little Bustard (Otis tetrax) in Kostanai Region
Abstract: The Great Bustard and the Little Bustard are emblematic species of Kazakh steppes. Populations of these birds were numerous in the middle of thelast century but in the early 1970’s they fare on the brink of extinction. Thispaper is based on a long-term observation in Naurzum Reserve and adjacentterritories in 1977-2014 and on territory of Kostanai Region in 1998-2014,as well as literature data. The paper provides information on the populationdynamics of the Great Bustard and the Little Bustard in Kostanai region, thefactors influenced on decline in their numbers, and the current state of theirpopulations. Population dynamics of Little Bustard during the end of 1990thand until 2010 characterized by decreasing of its density, that was most visible in feather-grass steppe. In 2006-2012 the number of Little Bustard variedfrom year to year, but dynamics from habitat to habitat had sometimes different trend. Since 2012, experienced rapid population growth, which wasprobably due to the appearance of the gregarious locust forms. The situationwith the Great Bustard is absolutely different. The number of this specie in thepast 40 years is maintained at an extremely low level, without visible changes.Key words: Great Bustard, Kostanai Region, Little Bustard, populations, number.