Bluebirds are small birds that feed on small fruits, insects and spiders. They build their nests in cavities of trees or in wooden boxes provided to them (like this one) by humans. Female bluebirds lay four or five eggs in a clutch and after sitting on them for two weeks, they will hatch into little baby birds. This usually happens twice a year for female bluebirds. It is not out of the ordinary for a bird from the first set of eggs to stick around to help the mom with her second batch. While bluebirds are considered quite common, their population has been consistently decreasing for the last century. This is because of the introduction of the European Starling and the House Sparrow into North America. These species compete with bluebirds for nesting sites. These are aggressive birds that can fit anywhere a bluebird can. The House Sparrow and European Starling chase away and sometimes kill the bluebirds already dwelling there. Also, the wild berry population is decreasing. The ones that remain are usually eaten by the sparrows before the bluebirds can get to them. To help out our native bluebirds, Fern Hollow built birdhouses. The birdhouses, such as the ones you see here, can give the bluebirds more choices for nest building and can help increase the bluebird population. You can learn more about bluebirds at: North American Bluebird Society