Habitat loss and habitat fragmentation are the most significant problem facing bird populations in Vermont.
- Habitat loss reduces the number of individuals that can be supported in a given area.
- Habitat fragmentation indirectly reduces bird population sizes by resulting in higher nest predation rates and lower food availability.
- Many declines seen in the Atlas can be attributed to one or both of these factors. For example:
- Land in hayfields and pastures was converted to development or reverted to forest, and many bird species that depend on open agricultural lands occupied much smaller distributions (Bobolink, Vesper Sparrow, Eastern Meadowlark, Horned Lark, Grasshopper Sparrow, Upland Sandpiper).
- As farms were lost and shrublands matured, shrub species also declined (Field Sparrow, Eastern Towhee, Brown Thrasher).
- Populations of species that occupy habitats that have been stable or increased in area have held their ground or grown.
- Forest-interior species probably benefitted both from the maturation of existing forests and a decrease in habitat fragmentation as once open areas reverted to forest.
- Little change was noted in the extent of montane forests of spruce and fir in Vermont, and likewise little change was noted in the distribution of species associated with these forests (Bicknell’s Thrush, Blackpoll Warbler).
- Wetland-associated bird species, associated with a habitat that changed little in extent, also showed little change in their distributions.
Bird populations may tolerate some level of loss and fragmentation, only to decline precipitously once a threshold is crossed.
Addressing the threat posed by habitat loss and fragmentation is straightforward: more habitat is better than less, and large blocks of habitat are better than isolated fragments of habitat.
- Dedicate some land to conservation (e.g., easements or public ownership)
- Encourage use of remaining lands in ways that can be compatible with maintenance of bird habitat (e.g., forestry and agriculture).
- Establish local planning rules that encourage clustered development and discourage converting forests and fields to commercial or residential uses.
- Provide incentives for land uses that result in the retention of natural vegetation, such as the Current Use valuation system.
- Promote incentives (e.g., Farm Bill programs) that encourage land retention rather than selling for development
- Strong regulatory backing for the wise stewardship of lands and waters (e.g., Act 250) is an important tool for bird conservation.