Marja R., Keerberg L. & Elts J. (2025) Night-time movements and roosting habitat selection of Grey Partridges Perdix perdix in the agricultural landscape. ARDEA 113 (2): 16-16

Globally, farmland birds have been on the decline. To understand or even halt these declines we need more knowledge on how birds use the agricultural landscape. While much is known already on habitat selection by farmland bird species during the day, we know very little about habitat selection by diurnally active birds and their behaviour during the night. This study focuses on the night-time behaviour and roosting habitat selection by Grey Partridges Perdix perdix. We investigated (1) the movements and distances travelled during the night-time, from the original roosting site to another site, (2) distances between roosting sites on consecutive nights and (3) roosting site habitats and temporal variability. We used GPS/GSM transmitters to collect data on night-time movement parameters and roost habitat use of 24 Grey Partridges (14 females and 10 males, 927 roosts) tagged in the years 2021–2022, primarily in Eastern Estonia. The results showed that on 422 nights (45.5% of cases), Grey Partridges moved from their original roosting site to another site during the nighttime for unknown reasons. They did not move far, males averaged 108 m and females averaged 70.4 m. The nocturnal movement of Grey Partridges did not depend on their sex. However, there was a statistically significant difference in the study periods, as night-time movement distances from January to March (mean: 155.0 ± 264.0 m; ±SD) were longer compared to night-time movement distances from April to June (44.9 ± 98.8 m) and from July to August (24.3 ± 56.7 m). Additionally, the nocturnal movements observed in July–August and October–November (84.6 ± 101.0 m) were statistically different. The distance between the roosting sites did not depend on sex or on whether the individual was stationary or not in the previous night. Grey Partridges mostly selected winter cereal and winter oilseed rape fields and grassy habitats as roosting habitats. There were seasonal differences in roost habitat use.