The use of man-made structures as nesting sites by birds: A review of the costs and benefits

Bird populations are often limited by the availability of suitable nesting sites and nestboxes are commonly provided with the explicit intention of increasing the availability of nesting sites. However, birds also regularly nest on man-made structures such as houses, uninhabited buildings such as barns and factories, bridges, metal pipes in fences and pylons that are not intentionally provided for breeding birds. Such man-made structures are widely used as nesting sites by a range of birds and their primary advantage is that they often provide nesting sites in areas where they are limiting. However, the primary disadvantages of such structures are that they sometimes act as ecological traps by attracting birds to nest in suboptimal areas, the nesting birds sometimes negatively impact other species and their temporary nature means that they can be dismantled and hence, lost as nesting sites very quickly. Despite such potential drawbacks, the evidence suggests that man-made structures provide suitable nesting sites for a range of bird species globally, and I urge practitioners to use such structures more widely as a conservation tool for conserving endangered birds.