Hi Sarah, one of mine went blurry when nest was not even in use ... dismantled during winter & inspection revealed water penetration, came apart quite easily & dried out but, of course, you'll have to leave yours until end of nesting season now! If you're lucky it might just be poo on the outside !
l know it's not quite the same but my outside trail cam lense goes misty when the weather over night suddenly drops causing condensation, could be that, does it clear has the day warms up? yas
Thank you, I think that's what it may be. Never mind always next year.