Bird Leucism is creeping up in lots of other birds as well. It is thought to be caused by stress and also by damage to the feathers, but like us humans who have more grey hair after living a stressful life. Leucism is a serious threat to bird populations. Why? This causes a number of significant problems in the life of the bird. 1. Mating with other birds is decreased because of the different coloration. 2. Birds with more or all white/light color features cannot keep warm with the sun as they normally would? Why? the white of the feathers reflect heat away from the bird which is dangerous in colder seasons. 3.Their damaged feathers are easily destroyed and makes it very difficult to fly at faster speeds and/or for longer periods of time. Studies show that our eco system, global warming, pesticide use from home owners and farmers are causing great stress on animals, not just our bird populations.