We are currently doing research on heron nesting/reproducing in an urban context. Any examples will help a lot. Thanks!!
Hello! Probably there are some cases which are likely related to the urban growth. By the middle of the 20th century, drastic reduction of the grey heron number was noticed for the Moscow region - several colonies disappeared from at least four outskirt Moscow parks (Ptushenko & Inozemtcev, 1968; Zubakin et al., 1986). This can be associated with the development processes of the period, but the exact reasons need to be studied. Grey heron (most common nesting Ardeidae species in our area) is far not a synanthropic species in our country. But it often establishes its colonies closely to the small settlements where human disturbance is common but doesn't affect directly. It is quite interesting to analyze the locations of the colonies relatively to the human settlements or constructions. For example, one of the examined by us colonies (152 pairs in 2020) is located on the forest right between the highway (western boarder of the colony) and a forestry construction (sawmill) (eastern boarder). The distance to the closest settlement (village) is about 350m. The human-related cases of disappearance of the colonies known to me are caused by the direct impact of humans (for example, shooting and ruining of the colonies, construction building near the colony, deforestation). Maybe there can be found more examples of probably "urban-related" disappearance of heronries mentioned in Russian scientific literature, but it certainly will take time to raise and analyze this problem. It doesn't seem to be studied...
Thanks very much! In my case here (Kunming, China) heronries have boundaries defined/interrupted by artificial structures, roads for example. It seems that to "cross" them would mean failure in nesting. We once found a pair or two Little Egrets attempting that way, then after egg laying one day the parents vanished with broken eggs found on the floor.. Besides those very few nests had been built close to an entertainment facility, there are also natural enemies, squirrels and cats that could mess up the breeding cycle. I'm interested in linking examples together to see what all the possible factors could be underlying heronry disappearance and life span, because under natural (ideal conditions) one seems to exist for a rather long time. Thanks again for sharing your study :)
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