This behavior is almost exclusive to Lapwings of North West England and Greater Manchester in particular.
Large flocks of Northern Lapwings gather (sometimes many hundreds) from the summer months till the following March for daytime roosts on industrial buildings in the urban suburbs of Manchester.
They seem to favour big factory roofs and in particular those made of corrugated asbestos, but also have a liking for large supermarkets.
A study about the Northern Rooftop Lapwing by Greater Manchester Bird Recorder, Judith Smith was published in British Birds in January 2000 and highlighted some likely reasons to why these birds act in this manner.
Some of the key points of these findings...
- The roofs offer greater protection from ground predators such as foxes which are a constant threat at their traditional roosts on farmland and fields.
- The roofs provide warmth due to rising heat.
- There are greater ambient temperatures in urban environments.
- There is good shelter on the sills and ventilation outlets.
- Loss of fields and open ground due to urban developments are a possible factor.
- Large roofs with good all round vision are usually chosen.
- Asbestos corrugated roofing is commonly used, likely because it offers greater insulation and the gritty nature of this material offers greater grip for the birds than corrugated metal.
- The need to conserve energy in a safe environment especially in the winter months could also be an important factor.
This rooftop roosting behavior isn't exclusive to the Lapwings of Greater Manchester...Their close relations the Golden Plover have also taken to this practice in recent years!
Lapwings roosting on a factory roof in Audenshaw, Manchester in July 2008...