Chapter 5 - Conclusions & Recommendations
How does the information developed by the Stopover Habitat Survey help a refuge manager develop conservation plans and policies that protects the future of migrant birds? First, it allows us to draw some general conclusions about how migrant birds are using the Connecticut River Valley:
- The largest number of individual birds were observed at the southern end of the Connecticut River Valley (CRV), and declined with the progression of survey locations north (Chapter 3, Figure 2).
- A similar south to north pattern was observed in the number of bird species occurring within the survey locations during spring migration. More bird species were observed in the southern end of the CRV, than the north (Chapter 3, Figure 3).
- The "A" sites, those occurring immediately along the main stem of the Connecticut River, were most heavily used by spring migrants in all states and survey periods (Chapter 3, Figures 6 and 7). This was particularly true of censuses earlier in the season where "A" sites perhaps provide more food and protection. A number of factors may contribute to this: water temperatures in the lower elevation of the main stem CR may be warmer, these lower elevations sites are more protected from inclement weather than the more exposed upland sites, leaf-out of deciduous trees occurs earlier in the lower elevations of the CRV, and early warm temperatures and leaf-out contribute to greater insect abundance, earlier in the season, at lower elevations.
- The south to north pattern was again observed in habitat use, with larger percentages of migrants using "A" sites in the south. As the survey sites became more northerly, habitat use among the three habitat categories became more evenly distributed (Chapter 3, Figures 8, 9, 10). This may result from the mouth of the CR and lower main stem acting as a landscape feature used by a subset of Eastern Flyway migrants to orient north. Overall density of birds decreases by approximately 50 percent from south to north, as birds disperse from the main stem Connecticut River migration route.
If we were to stop our analysis here, we might draw an obvious conclusion, that "A" sites in the southern end of the CRV are the most important to spring migrants as a group. But this is only part of the story of how migrants are using the CRV. We need to be cautious not make an overly simplistic management recommendations that says because "A" sites in the south are most heavily used at certain times, we should focus all our attention on preserving southern "A" type habitat. On one level, this is an important observation, but it does not recognize individual species' behaviors or the beauty and complexity of how an ecosystem like the Connecticut River Valley works (Chapter 1).
The results in Chapter 4, Species Accounts, provides insights into the specific strategies and behaviors that particular species of migrants use in the CRV. Very early in the migratory season Yellow-bellied Sapsuckers are heavily concentrated in "C" sites in all states, with the most northern sample areas of Vermont having the highest density of any state. Upland forests of deciduous trees with their running sap are critical resources to Yellow-bellied Sapsuckers in the very early spring. Another early arrival, the Hermit Thrush, also shows a strong preference for "C" sites. Yellow-rumped Warblers, which feed on persistent winter berries, arrive a little later in spring migration and quickly make their way to "B" sites along tributaries. The Baltimore Orioles arrive still later, and as their numbers increase, so does their use of "A" sites. So while "A" sites are important to many species at some point in their migration, particularly as they move up the eastern Flyway and enter the CRV, they often dispersed into other habitat types depending on the individual species' migratory strategy. The role of "A" sites is an important part of the story, but not the whole story.
A third, and possibly the most critical factor in developing a stopover habitat management strategy is the role human land use plays within the CRV landscape. Native Americans traditionally used the Connecticut River as a corridor for transportation and commerce. This pattern accelerated with European settlement. Cities like New Haven, Hartford, Springfield, Brattleboro, and Hanover grew from small settlements into the centers of population and commerce we know today. Floodplain forests with their rich soils, as well as rockier up land locations were cleared for agriculture crops, pasture land, and in the harvesting of wood products. With this historical momentum, Interstate 91 today defines a corridor that stretches from the Long Island Sound to the Canadian border: the Connecticut River Valley is home to over 2 million people. Interstate 91 not only links the necklace of urban centers along it's route, it also clearly defines the corridor as a place for expanded commercial and residential activity. Often this important economic activity and growth results in a haphazard regional landscape of sprawl that does not take into account water and air quality, historical features, efficient transportation patterns, or wildlife communities. From the migrant stopover habitat perspective, this translates to habitat loss and fragmentation (Chapter 1).
- Because different bird species use different migratory strategies in regard to habitat use, a regional mosaic of of stopover habitat types is required. A Geographical Information System (GIS)-based regional stopover habitat inventory of the CRV should be conducted to aid in the development of a comprehensive strategy. The "A," "B," and "C" habitat categories can serve as a baseline for developing and defining stopover habitat protection categories. This inventory can be used to identify stopover habitat, the amount of habitat within any particular category, and the spatial relationships (insularity, connectedness) within and among habitat types.
- Migrant birds are a good environmental indicators; preservation or enhancement of migratory bird stopover habitat will directly benefit breeding and wintering birds, and a suite of ecologically-related fauna and flora. Decisions regarding habitat protection resulting from the inventory should be evaluated in the context of regional planning and growth pattern data.
- The process of developing a regional habitat inventory and protection strategy should be conducted in consultation with local and regional conservation organizations, municipal planning agencies, land trusts, conservation commissions and planning boards. A significant number of land use decisions that lead to both habitat fragmentation and environmentally sound planning are made at the local level. Conservation leaders in localities that do not currently have land trusts should be encouraged to establish them. To encourage broader citizen participation by those concerned with sprawl and habitat loss, a CRV-wide educational program should be established, encouraging citizens to participate in town and municipal government decision-making bodies, local conservation organizations, and land trusts.
- Areas adjacent to the Connecticut River that have already experienced significant land development, or where rapid development is anticipated for the coming decade, should receive immediate attention. This would include areas in the southern end of the CRV where historical land use patterns and suburbanization have significantly impacted "A" type habitats and their availability for conservation.
- In areas were available land is limited for habitat protection, habitat reclamation projects should be evaluated. This would apply particularly in areas where existing urban and rural centers are re-examining their Connecticut River waterfronts in regard to revitalization projects and re-use of former commercial and industrial lands. Reclaimed stopover habitat should be considered a cost effective land use activity that enhances recreational opportunities and quality of life.
Additional Research Questions and Opportunities
- Because of the landscape scale of the study area, nearly all migrants are also breeding species somewhere within the Silvio Conte National Wildlife Refuge. Studies within the CRV that help clarify when a bird ceases being a migrant, and becomes a breeder on territory, would provide insights into the south-north patterns observed and dispersal along the migration route. This would also help understand the relationship between stopover habitat and breeding habitat, and the migratory strategies of the species that are both migrating and selecting breeding territories within the CRV.
- What are the similarities and differences between spring and fall migration patterns and habitat use? How would this comparison influence stopover habitat protection strategies? A companion study during fall migration is required to address these questions.
- Banding and behavioral studies focusing on individual groups of species, or selected species would aid in identifying migrant stopover duration within habitat types, how specific habitat types are being used, and the physiological impact of migration in regard to weight gain and fat deposition.
- Periodic replication of the stopover habitat survey over an ecologically significant time frame (e.g. 25-50 years) would provide greater insight in distinguishing the relationship between predictable year to year variability, and ecologically more significant long-term population and habitat use trends.
- Studies that look more closely at temporal and spatial patterns involving habitat use by migrants, temperature, leaf out, and insect abundance would greatly aid in understanding migration strategies and habitat use within the CRV.
- A study within the CRV that examined human perceptions, attitudes, and values in regard to lifestyle, quality of life, economic development, open space, wildlife, and conservation would aid in guiding economic and conservation planning, as well as informing public policy development and conservation education outreach efforts.
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