Kolonie lęgowe czapli siwej Ardea cinerea znane są z obszaru całego kraju, jednak ich rozmieszczenie w południowej Polsce jest silnie rozproszone. W dniu 17 marca 2014 roku w drzewostanie sosnowym położonym w pobliżu kompleksu stawów rybnych w miejscowości Zborowskie w gminie Ciasna (powiat lubliniecki) odkryto niewielką kolonię lęgową czapli siwych. Policzono 25 zajętych gniazd zlokalizowanych na wysokich sosnach. Ponowna kontrola czaplińca po dwóch miesiącach (19 maja) wykazała obecność 36 par zajmujących gniazda. Wywiady przeprowadzone z pracownikami gospodarstwa rybackiego pozwoliły ustalić, że czapliniec ten istniał już w roku 2013. Nowo odkryta kolonia lęgowa jest drugą tego gatunku w województwie śląskim i pierwszą złożoną wyłącznie z gniazd czapli siwych. Najbliższe czynne dwa czaplińce od omówionej tu koloni zlokalizowane są nad Kanałem Gliwickim koło Pyskowic (43 km w linii prostej) oraz koło miejscowości Stobrawa (72 km w linii prostej) w województwie opolskim
The breeding phenology of the Grey Heron Ardea cinerea L. was investigated in three colonies situated on the Baltic Sea coast in Poland in 1999–2002. The heronries differ in localization (inland vs coastal) and local climate conditions. In inland location, air temperatures in spring were lower by 1.1–1.5°C and ice cover was present on foraging grounds longer by 19–29 days comparing to coastal ones. Herons occupied all colonies in similar dates (multi-year median date for all colonies: 5 March). However, birds from one coastal heronry tended to start breeding 9–10 days earlier (multi-year median date: 28 February) than birds from other colonies, what might be possible due to early presence of herons in the vicinity. Accessibility of foraging grounds (lack of ice cover) in spring was an important factor affecting the onset of breeding as dates of colony occupation, egg laying and hatching were positively correlated with the dates of last ice cover occurrence on the foraging grounds (r> 0.75, P <0.05). Intercolony differences in hatching dynamics might result from various frequencies of replacement clutches, and nests of late breeding subadults. In one season (2002), the number of medium-aged chicks per nest and fledging success were negatively correlated with the hatching date. Since chick mortality rate during last three weeks before fledging was not correlated with hatching date (suggesting similar food conditions in the course of the season), worse breeding parameters late in the season could be reflected in the lower clutch size or/and hatching success/chick survival rate during the first three weeks in nests of late breeders (i.e. subadults and replacement breeders).
Life history traits of birds like survival or reproduction are strongly related to habitat features which affect food and nest-site availability. However, impact of habitat variables on life-history traits, which may be scale-dependent is barely studied. We investigated the relationships between landscape features and productivity (expressed as the number of 21–38 day old chicks per nest) of a colonial waterbird, the Grey Heron Ardea cinerea in northern Poland. In 2014 we analysed the landscape features (hydrographic features, habitat area, habitat patchiness and distances to the nearest water bodies, coastline, rivers/canals, buildings and roads) around the six colonies. We analysed all those features in four spatial scales around the colony: close proximity of the colony (0–1 km), closer foraging grounds (0–10 km), far foraging grounds (0–20 km) and far foraging grounds excluding close foraging areas and proximity of the colony (10–20 km). The differences in productivity among the colonies was not significant in the studied year (mean number of chicks ± SD: 3.57 ± 0.52). At each spatial scale excluding 10–20 km radius, Grey Heron productivity increased with increasing habitat heterogeneity and decreased with increasing length of rivers/canals and area of pastures. The results of this study indicate that the spatial scale of 0–10 km was the best to indicate relationships between landscape features and productivity in herons. Distance to the nearest river/canal banks, buildings and roads were related positively to productivity. Our study revealed the importance of landscape complexity of aquatic and terrestrial habitats for the Grey Heron productivity.