Goldcrests are the smallest European bird. Because they are so small, they need lots of energy to stay warm in the winter. They lose 20% of their body weight on a cold night! During the day, they eat at least several times their body weight in insects and spiders. Sometimes, they are so busy looking for food that they aren't even afraid to get close to people. You can practically touch them. Goldcrests only make their nests in coniferous trees. A part of the Dutch goldcrest population migrates southward in early September for the winter.