Jackdaw populations increase each year with birds from Europe joining the flocks. In recent winters, Scandanavian jackdaws, with striking white neck collars have been identified. As jackdaws pair for life, strong bonds are formed during the winter by young birds. By spring, birds are engaged in mutual preening and courtship. During these courtship periods, males will also engage in feeding the females, suggesting to them that they would make good mates and providers for their young.
Most jackdaws breed for the first time when they are two years old.
While many birds proclaim their territory by singing, the harsh, unmusical notes of the jackdaw are not often equated with the songs of the robin or blackbird. But jackdaws are true songbirds. In fact, the songs of jackdaws are quite complex and include a variety of chatters and harsh notes . . Unlike robins and blackbirds, both male and female jackdaws engage in singing, and the quiet songs can last for up to five minutes at a time. Breeding Behaviour Jackdaws nest in loose colonies with some choosing to nest alone, away from the hustle and bustle of such gatherings.