Anti-pigeon Spikes

Feral Pigeons are happy living close to humans and make the most of human-provided food and lodgings.
A bizarre example of this is the pigeon above who used anti-pigeon spikes at Totteridge Tube Station to assist in supporting her nest.

She used the anti-bird spikes two consecutive years as convenient nest supports.

These under the railway arches at Mill Hill also take advantage of human construction - the arches for shelter and the anti-pigeon spikes for nest support.