Birds entering my loft

[taz777]

I've got a problem with birds finding their way into my loft. As my property is being refurbished the loft hatch is always open and some of the upstairs ceiling have largish holes in them where lights have been removed. The birds find their way through these holes and into the main house.

Which tradesman would I call to check for gaps in my roofline and plug them to stop birds entering my loft space?

 

[taz777]

I should add that the loft is currently clear of everything, including loft insulation. I'm wondering if this is the issue or not? It won't be insulated for another four weeks.