Rooftop roosting gulls - developing the ongoing study

Alan Dean, John Sirrett and Jim Winsper

In connection with our request for information concerning gulls that roost on rooftops, the time is fast approaching when Herring Gulls and Lesser Black-backed Gulls gather at their rooftop breeding sites within our Region. Such gatherings might provide an opportunity to find out if those birds that arrive early, might roost at these sites before the commencement of any breeding activity. While this activity at this time of year might be considered a prelude to breeding, it will however, provide evidence that roosting on rooftops is a natural or developing tendency within their overall behaviour. This, if proven, will certainly assist the study. Guidance in locating previously known rooftop breeding colonies can be found by visiting: https://irp-cdn.multiscreensite.com/cafb889d/files/uploaded/Roof-top%20Nesting%20Gulls%20-%20Birmingham%20JRW.pdf and reading tables 1. and 2. (It might well be the case that some of the colonies mentioned in this report, published in the 2011 WMBC Annual Report No. 78, have since changed location or no longer exist). This notice also serves as a reminder that this will be the first opportunity for the wider birding community to explore the possibility of birds roosting on rooftops during their post breeding dispersal activities, July through September. Scroll down to view our previous post from 2022 that presents our findings, together with a request for information. The potential for this to be investigated on a wider scale during this period this year, 2023, offers an exciting opportunity to develop any findings that arise from your investigations.

Observations of a purposeful movement of mixed age Lesser Black-backed Gulls and smaller numbers of Herring Gulls heading to a rooftop roost site during the post breeding dispersal period (July to September), has prompted a meaningful discussion between Alan Dean, John Sirrett and myself in connection with gulls that appear to be adapting their habits to include roosting on rooftops. Other than the aforementioned species, there is also evidence that Black-headed Gulls are involved in the same behaviour. A lot more information is required about this development in gull behaviour and those involved in the discussion are prompting a research study that is intended to add detail and explanation to preliminary findings. The research will be expanded in coming months, but preliminary findings will certainly assist our investigations. From here on, and going forward indefinitely as the suggested behaviour evolves, will involve birds roosting on rooftops during the post breeding dispersal period and thereafter during the autumn and winter periods.

The next development in our research will involve a paper in the December issue of WMBC News that promotes the research study and presents a detailed account of what we wish to achieve. This will include suggested guidance that will assist WMBC members, and possibly the wider birding community, in providing valuable information.

In the meantime, any information on rooftop roosting gulls will be extremely helpful and we welcome any findings that supports this research study. Currently, post breeding dispersal from the regions breeding gull colonies is taking place and this provides an immediate opportunity for observers to witness movements to possible roost sites on suitable rooftops. Observations of birds moving along narrow flight-lines in a purposeful direction during the dusk period just before dark, might well offer an indication that these birds are going to roost. Tracking these flight-lines could reveal their destination to be suitable rooftops. Information on this behaviour and its associated locations will be most welcome. Indeed, any information that you consider to be associated with rooftop roosting gulls is considered important to the aims of this research (e.g. the direction of dusk flight-lines during the period July to September or night-time gull vocalisations from rooftops outside of the breeding season). Please send details to me, Jim Winsper at: jimwinsper@gmail.com

Needless to say, and however rewarding, any involvement in this research that is carried out largely during the hours of dusk and darkness, requires due discretion and caution.

Jim Winsper