For the second year running, no Common Terns bred in Tower Hamlets in 2017. And unlike last year, when birds appeared to be incubating at East India Dock Basin and Blackwall Basin but nests failed, this year there were no nesting attempts at all.
At East India Dock Basin, where terns nested successfully up to 2015, a few terns appeared as usual this spring, and a couple of pairs were active around the rafts between May and early July. Territorial behaviour, including courtship displays and aggression towards other terns, were observed, but there were no nesting attempts.
As last year, a pair of Coots were nesting on the terns’ preferred raft by the time the terns arrived, and were seen chasing terns away from the raft on a couple of occasions. A pair of Lesser Black-backed Gulls, another aggressive species and potential predator of tern eggs and chicks, nested on one of the other rafts, providing further deterrence. Low water levels and too much vegetation growing on the rafts also remain potential deterrents. All of these factors may have encouraged the terns to opt for the rafts across the river at Greenwich Ecology Park, where there was a marked increase in the number of nesting terns this year. It will be very difficult, if not impossible, to improve potential nesting conditions for terns at East India Dock Basin until the basin can be de-silted.
There have been no reports of terns showing an interest in rafts anywhere else in the borough this year. At
Blackwall Basin, the rafts were placed right up against the wall, close to where the Wood Wharf development is taking place, so it is no surprise that no terns tried to nest. Much more surprising is the lack of any interest by terns in the rafts in Millwall Inner Dock. Two rafts were placed in this former tern breeding site last year and both are in pristine condition. While one is perhaps a little too close to the dock edge, the other seems to be in a good location, so it is a mystery why it was not used. There is also a raft on Shadwell Basin, where terns have nested in some recent years, but no reports were received this year.
Several new rafts are due to be installed in the Millwall and West India Docks in the next year or two as part of the biodiversity mitigation for the Wood Wharf development. Let’s hope that these charismatic birds, a priority species in the Local Biodiversity Action Plan, find some of these, and/or the rafts in Millwall Inner Dock and Shadwell Basin, to their liking in future years.