Why do land birds migrate at night?
Birds’ instinct to migrate is largely influenced by sudden shifts in temperature, available daylight (photo period), moon phases and light tail winds. The evaluation of land bird migration determined that flying conditions for long-distance travel are most favourable under the cover of darkness. These favourable conditions include less potential for predation, cooler temperatures to help maintain body temperature and less inclement weather
How does migration influence bird-building collisions?
Artificial lighted structures can disorient night migrating birds as they tend to fly toward and hesitate to leave these lit areas. As day breaks, birds quickly descend to the ground in search for vegetated habitat where they feverishly forage for food to replenish their depleted energy reserves. This dramatic rise in the concentration of birds in built environments increases the potential for bird-building collisions.