Fighting over low tide

As I walked to the ferry stop this morning the tide was especially low - and for some reason this causes a furore in gull world. Twirling squawking shrieking they fight over the water swirling out of the lock - I think it might be rubbish and disgusting slimy things found in the bottom of the Thames like the inevitable teaspoon in the bottom of the sink.
In the distance on the left you can see the Hilton pier and the Hilton ferry. The tide was so low the Hilton ferry couldn't land and people had to wait for half an hour for the tide to come in again before they could he deposited back at the Hilton.
This never happens at the canary wharf pier.