The gulleries: pairing territories

For a little while now the gulls have been reclaiming the islands. the thinly spread Herring and Lesser Black-backed Gulls had already been mooching around their sites for a couple of weeks, while in the last ten days the numbers of Black-headed Gulls taking up position on the islands has increased substantially.

As appears to be the norm, best sites are claimed first. Here on the Medway, as elsewhere, higher ground goes first. The textbooks point to experienced breeders returning early and claiming the prime sites. For somewhere like Greenborough, that means the central mounds and few of the more vegetated high spots on the seawall. For somewhere like Millfordhope, the East Enders are back, but not much activity from the lower-lying West Enders yet.

Inferior sites are also ignored in these early days; no activity yet on the barer walls of Nor, but the well-vegetated adjoining Friars nesting areas are re-occupied. Nearby Bishop is very busy as well, where the first 'dreads' are now taking place (all the birds rising silently together).

In any tidal cycle the highest seen each month are the 'springs'. We have one more set of the very high spring tides to go before breeding can get going in earnest. Although it might look like breeding is starting now, some of the texts point towards 'pairing territories' being used during this early period. Personally, I suspect we see a good deal of this here. I base this on the birds at the main colonies never being anywhere near as tightly packed as they will be once settled. Pairing territories are for displaying and bonding, and are always somewhat bigger than an actual nest territory.

So other birds set theirs up nearby; on the mud (or water), or along the shoreline (I often encounter pair displays on the Sharps Green car park beach)- By the time of the April spring tides the birds will be packing themselves in tight, but many will be washed away.

A hundred years ago the crews of the local fishing boats had a name for the time following such a spring- the weeks between the highest of the regular spring tides when much of the breeding could take place- 'Bird Tides'. This year's Bird Tides look challenging for the Medway gulls:

In the estuary a tide over about the 5.9 metre mark causes problems for any of the lower-lying nests. They can put up with some inundation, but if there are strong winds/ poor weather at this time, as in May 2015, matters will be much worse. The forecast height for this year's May springs will certainly cause quite a few problems for many nests, but gulls are a resilient bunch and relaid clutches then have a fair chance of success unless, of course, we suffer low pressure over the lower springs in June and July.

Springs always make for interesting viewing, especially with forecast heights creeping up year on year. The dates are already highlighted in my diary.

Spring tide, April 2015; prelude to the Bird Tides

Foreground- Greenborough seawalls; behind, higher land on Burntwick

During the Bird Tides:
The west end of Millfordhope, with Slayhills saltings behind,
spring tide, May 2015

A short cross-section of the Bishop colony on May springs, 2015