Landbird Population Trends in the Northern Colorado Plateau Network, 2021

Mourning dove

NPS

Why Monitor Landbirds?

Birds occupy various levels in the food web and play an important role in the flow of energy through ecosystems. Because they can be sensitive to habitat change, birds are good indicators of ecosystem integrity. They also have strong public appeal—unlike many other animals on the Colorado Plateau, birds are commonly visible to park visitors. Data from the relatively natural habitats of Northern Colorado Plateau Network (NCPN) parks will provide status and trend information useful in comparisons with more-impacted areas.

To know which species to manage for, park staff need to know which species are present. Declines in certain species or habitats—or increases in others—can alert managers to potential ecosystem change. This information can also be combined with other data, such as climate variables, to do vulnerability assessments (for an example, see this article about how drought is impacting Northern Colorado Plateau landbirds).

Data from this monitoring are useful for park planning documents, such as Natural Resource Condition Assessments and State of the Park reports, and demonstrate the value of unimpaired national park landscapes and their value to bird communities.

Where are Landbirds Monitored?

Northern Colorado Plateau Network landbirds monitoring occurs at 12 network parks:

• Arches National Park

• Black Canyon of the Gunnison National Park

• Bryce Canyon National Park

• Canyonlands National Park

• Capitol Reef National Park

• Colorado National Monument

• Curecanti National Recreation Area

• Dinosaur National Monument

• Fossil Butte National Monument

• Natural Bridges National Monument

• Pipe Spring National Monument

• Zion National Park

How is the Monitoring Done?

NCPN landbirds monitoring assesses trends in breeding-bird species by habitat, rather than by park. During each breeding season, a partner organization surveys 15 transects in each of the three habitats of interest (low-elevation riparian, pinyon-juniper, and sage shrubland). Point counts and area searches are also conducted as part of a modified monitoring design at Pipe Spring National Monument.

What’s the Latest News?

Data collected over 16 years of monitoring reveal eight significant (p-value < 0.05) trends in population density. Six trends are declining; two are increasing (see table). In all, 117 population-density trends have been estimated across the three habitats—but most are not statistically significant.

Significant trends in landbird species population density across three habitats in 11 NCPN parks, 2005–2021.

Species	Low-elevation riparian	Pinyon-juniper	Sagebrush shrubland
mourning dove	↓	↓	–
white-throated swift	↓	↓	–
rock wren	↓	–	↓
vesper sparrow	–	↑	–
lark sparrow	–	–	↑

A total of 656 point-count surveys were conducted at 11 parks, detecting 105 unique species. New species were detected at park and monitoring program levels.

New species record for a park:

• Wilson’s snipe (Gallinago delicata) was detected for the first time at Colorado National Monument

Two new species were detected for this monitoring program:

• Swainson’s hawk (Buteo swainsoni) in Bryce Canyon National Park

• Wilson's snipe (Gallinago delicata) in Colorado National Monument

The following species were detected for the first time during the monitoring program for these specific parks:

Bryce Canyon National Park

• lazuli bunting (Passerina amoena)

Colorado National Monument

• northern mockingbird (Mimus polyglottos)
• western kingbird (Tyrannus verticalis)
• two Wilson’s warblers (Cardellina pusilla)

Natural Bridges National Monument

• Brewer’s sparrow (Spizella breweri)
• brown-headed cowbird (Molothrus ater)
• lark sparrow (Chondestes grammacus)

Pipe Spring National Monument

• greater roadrunner (Geococcyx californianus)
• ruby-crowned kinglet (Regulus calendula)

Since monitoring began in 2005, a total of 15,139 point-count surveys have been conducted in the 11 parks, detecting 178 unique species.

Low-elevation riparian habitat showed the largest number of significant decreasing trends. Only two significant increasing trends were seen: one each in pinyon-juniper and sagebrush shrubland.

In Pipe Spring National Monument, we detected 118 individuals of 34 species at point count and area search surveys in 2021. For the first time in this monitoring program we detected greater roadrunner (Geococcyx california­nus) and ruby-crowned kinglet (Regulus ca­lendula) in the monument. Sample sizes were too low for density trends to be estimated for the monument.

The results in this article were summarized from S. G. Roberts, E. L. Tymkiw, Z. S. Ladin, and W. G. Shriver. 2022. Status and Trends of Landbird Populations in the Northern Colorado Plateau Network: 2021 Field Season.

Print this brief