DU Mobile Apps
World Leader in Wetlands Conservation

Northern and Southern Rockies / Colorado Plateau - More Information

Background information on DU's Northern and Southern Rockies / Colorado Plateau conservation priority area
PAGE 123456
SIGN IN    SAVE TO MY DU    PRINT    AAA

The waterfowl population in the RCP is not known, although it is recognized that breeding densities of waterfowl vary greatly within the region (Table 3). This variation is largely attributed to wetland density and the availability of open water to attract and hold spring migrants. Wetlands larger than 0.4 ha receive most of the use by breeding ducks, although much smaller wetlands are also frequented. Considerably larger wetlands are needed to attract molting birds and fall migrants. Some intensively managed habitats achieve remarkable high breeding densities. For example, the 57 km2 Monte Vista National Wildlife Refuge (MVNWR) in Colorado's San Luis Valley averaged 107 duck nests/km2 over a 27-year period, and some individual wetland units exceeded 1,158 nests/km2 in some years (Gilbert et al. 1996). This compares favorably to nesting densities in the best prairie habitat. Moreover, at MVNWR the Mayfield duck nest success is estimated at 26-29%. The relatively unfragmented habitat and indigenous predator community typical of many areas of the RCP undoubtedly contributes to this high nest success. The combination of high nest success and potentially high breeding densities underscores the management potential of some portions of the RCP.

Table 3. Waterfowl breeding pair densities in portions of the RCP (from Ringelman 1992)

Waterfowl density

(pairs/km 2 )

Area sample (km 2 )

Elevation (m)

Location (habitat type)

0.62

93

2,285-3,047

Uinta Mountains, Utah (Upper Montane)

0.62

47

2,742-3,047

White River Plateau, Colorado (Upper Montane)

1.58

1,774

2,437-3,047

San Juan Mountains, Colorado (Upper Montane)

8.42

18

2,590-2,894

Park Range, Colorado (Upper Montane)

0.19

2,331

2,559-3,016

South Park, Colorado

(Intermountain Basin )

2.01

12,950

2,255-2,437

San Luis Valley, Colorado

(Intermountain Basin )

10.50

1,549

2,437-3,047

North Park, Colorado

(Intermountain Basin )

A few waterfowl populations depend heavily on the resources provided in the RCP. The mid-continent trumpeter swan population is centered in the region, and is heavily dependent on the submergent vegetation that develops in the wetlands and river systems of northwestern Wyoming and northeastern Idaho. Despite the many problems these birds encounter when trying to over-winter in this area, many individuals persist in being non-migratory. This poses special management problems. In addition to swans, the entire Rocky Mountain population of greater sandhill cranes is largely confined to the RCP, from their primary wintering grounds in New Mexico to their breeding habitats in Idaho and Montana. During both spring and fall migration, the entire population migrates through the San Luis Valley, Colorado. Cranes feed heavily on waste barley and other agricultural and natural foods during their stay in the Valley, during which they acquire important nutrient reserves. Wetlands of the San Luis Valley are vital as loafing and roosting sites for these cranes.

PAGE 123456
SIGN IN    SAVE TO MY DU    PRINT    AAA

Free DU Decal

Receive a free DU decal when you signup for our free monthly newsletter.

  DU is a Better Business Bureau Accredited Charity DU Holds a 4-Star Rating with Charity Navigator