The increasingly urban status of the Cattle Egret Bubulcus ibis in Uganda, with some observations on its variable breeding seasons and associated species
The increasingly urban status of the Cattle Egret Bubulcus ibis in Uganda, with some observations on its variable breeding seasons and associated species
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乌干达牛背鹭的城市地位日益提高，及其繁殖季节变化和相关物种的一些观察
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
D. Pomeroy
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作者：
Esther Toloa;M. Kibuule;D. Blasberg;D. Pomeroy
长期以来，牛鹭一直以其不断扩大的地理范围而闻名，近年来，在拥有150多万人口的坎帕拉和其他地方，牛鹭也变得越来越城市化。15年前首次记录到它们在坎帕拉栖息，现在它们的数量超过了16000只，分布在几个地点，其中大多数也已经繁殖了几年。然而，筑巢的数量远远低于每晚来栖息的鸟儿的预期数量。坎帕拉的繁殖呈现双峰型，可能是因为一些鸟类一年繁殖两次--这在一定程度上解释了它们数量的快速增长。繁殖的时间与降雨量有关，但不同地点和不同年份之间的差异可能比预期的要大。一些鸟类可能一直在现在的坎帕拉地区觅食。今天，一些人在城市的主要填埋场觅食，但大多数人去农村，在那里他们对丛林蟋蟀、蚱蜢和其他昆虫的消费想必对农民有利。总体而言，在这个近赤道的城市里，牛背鹭现在可以被认为是城市化的，因为它的繁殖和栖息，以及某种程度的喂养。
Cattle Egrets Bubulcus ibis, long known for their expanding geographical range, have in recent years also become increasingly urbanized in Kampala, a city with over 1.5 million people, and elsewhere. First recorded roosting in Kampala over 15 years ago, their numbers now exceed 16 000, spread across several sites, at most of which they have also been breeding for several years. However, the numbers nesting are far lower than might be expected from those that come nightly to roost. Breeding in Kampala shows bimodal peaks, perhaps because some birds breed twice a year—which would partly explain their rapid increase in numbers. Timing of breeding is linked to rainfall, but shows more variation between sites and between years than might be expected. Some birds may always have fed in the area that is now Kampala. Today, some feed at the city’s main land-fill site, but most go to the countryside where their consumption of bush-crickets, grasshoppers and other insects is presumably beneficial to farmers. Overall, for breeding and roosting, and to some extent feeding, Cattle Egrets can now be considered as urbanized in this near-equatorial city.