Abstract:

Night counts of calling Corncrakes were carried out on 34 survey routes in Latvia during the breeding seasons of 1989-2000. The average breeding density increased in the study period from 0.84 to 1.36 calling males per km2. Using the data from the Sn counts have been done since the 1960s, and the decrease in proportion of meadows in Latvia, as well as the estimate of Corncrake numbers in Latvia in 1996, I calculated Corncrake numbers in Latvia in the past. The estimate from this model is consistent with previous estimates, e.g. for 1995, 20 118 v 22 735 and for 1989-1994, 3726-10 432 v 3 000-10 000. The results suggest that previous warnings that 3 000-10 000 was an underestimate, are incorrect. I now assume that the Corncrake population reached its minimum during the late 1980s and early 1990s and is currently increasing, but is still lower than it was at the beginning of the 20th century. Statistically significant negative correlation (r=-0.48; P=0.045) was found between total pesticide use in Latvia in year t and Corncrake numbers in the Sn pesticide use indicates reduced income from crop production and thus a lower-intensity (ie nature-friendly) agriculture. Abandonment and low-intensity use of agricultural lands in the1990s are the main reasons for the increase of Corncrake population, but favourable habitat will be lost in the near future by afforestation and intensification of agriculture. My final conclusion are none) or legal protection, but because of the crisis in agriculture after the end of the soviet occupation of Latvia. Thus the increase in Corncrake numbers may not persist.