Loss of habitat to urban and agricultural development, along with liberal pesticide use and expansion of invasive species, has had widespread detrimental effects on birds. Fragmentation refers to the breaking up of their once continuous habitats into smaller, unconnected habitat, a result of human activities such as land conversion and development. The resulting small, isolated patches of habitat create difficulties for birds to find food, water, and shelter within intact habitats. Habitat loss and fragmentation is one of the leading threats to biodiversity.