Blue tit question

Alun

So, I now have a permanent motion detection camera set up in my nest box and to my surprise late last year I noticed I had a resident blue tit, who stayed overnight in the box, leaving at sunrise and returning at sunset, also occasionally taking shelter if the weather took a turn for the worse.

Then a week or so ago, I started noticing a different blue tit, obvious because of the head markings also paying the odd visit during the day, and then for a couple of nights they both occupied the box, snuggled up in opposite corners.

Now, it's the latecomer who spends the night, with the original bird still popping in during the day.

The two birds look quite different .. one is slightly larger with brighter more vivid colours and a solid head cap. The other, the latecomer, is smaller, less vivid and generally a bit scruffier all over. It also has a very patchy, blotchy head cap.

Any idea what the situation is here? Is the second bird just in bad condition, might it have a disease of some sort? Is one likely to be a male, the other female? Are they a potential "couple"?

I've included a couple of screen shots from my videos of the two birds below ...

First bird



Second bird

ytpe2r5bxkn0c1

The second bird just has some coloration issues, not unusual. One roosted through the Winter in the box and this is now a likely breeding pair. They may build and occupy a nest in the box but they are also liable to build and reject the nest too, as they can build several trial nests.

Alun

Good to know it's just a colouration thing with the second bird. Is there anything to indicate which one might be the male and which one the female? It doesn't come across so much in the stills, but observing them on the video footage, bird one is a bit bigger than bird two.

ytpe2r5bxkn0c1

Size doesn't distinguish the sexes in Blue Titus, but the female can often be paler.

OpenYourEyes

The females are generally a bit duller than the males, though it can be hard to tell. The wing coverts of the male are more blue, whereas with females there's less blue and more of a greenish colour (though this is very difficult to tell without having the bird in the hand i.e. when ringing). And in some extreme cases you can tell by the dark band at the back of the neck - very thick is male, very thin is female.