Bluetit Diary    Mar 2016 (5)

First the owner of the box went inside.  I don't know whether this was in response to a stranger taking an unwelcomed interest in the box, or whether it was just a coincidence.

Here comes the newcomer.

At this stage, it didn't try to go inside ...

 ... but took up position on the entrance hole and looked inside.

This is what it saw!

The newcomer peered further into the box.

The bird inside immediately came to the hole itself and this caused the newcomer to retreat a little.

Here you can see that the bird already in the box is making a great fuss ...

 ... which causes the newcomer to recoil back in surprise.

Here it looks as though it tried to fly away ...

 ... but finds it cannot because one of its legs has been caught by the bird inside the box,

All it can do is to flutter and flap and try to get away.

We have seen this tactic by the bird inside the box several times before and puts the attacker at a severe disadvantage.  It is too close to the box to get away by flying and it appears it finds it very difficult to release its leg from the other bird's grip.

There is presumably also a danger of damaging the trapped leg - or even of breaking it which would be disastrous.

All it can do is to try to fly away which usually results in it going round and round, but still held firmly by the bird inside.

It looks as though the inside bird is gripping the other's leg in its beak!

All he can do is to flutter and twirl around in the hope that he can get his foot free.

Round and round he goes.

There must be a danger of severe damage to his foot.

The bird in the box still seems to have a grip on the attacker's claw.

Finally he gets free ...

 ... and immediately he turns to fly away ...

 ... and lick his wounds (or whatever the bird equivalent is!)

The bird in the box stayed here for quite a long time looking to make sure that the attacker was not going to return.

The bird inside the box appears to be in much the stronger position!