Landbird Population Trends in the Northern Colorado Plateau Network, 2019

Bald eagle. (USFWS/Karen Laubenstein)

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.

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?

Over 14 years of data collection, 14,273 point-count surveys have been conducted in the 11 parks, detecting 173 unique species. During the 2019 field season, 655 point-count surveys were conducted, detecting 111 unique species.

In total, 134 population-density trends were estimated across the three habitats for 2018. Twenty-one of those trends were significant (p-value <0.05), including 16 negative trends and 5 positive trends. There were suffcient sample sizes to estimate the densities of 63 species in at least one of the three habitats surveyed.

Significant trends in landbird species population density across three habitats in 11 NCPN parks, 2005–2019.

Species	LR	PJ	SA
Mourning dove	↓	↓	–
White-throated swift	↓	↓	–
Bushtit	–	↓	–
Rock wren	↓	–	↓
House wren	↑	–	↑
Mountain bluebird	–	↓	–
Yellow warbler	–	–	↑
Grace's warbler	–	↓	–
Black-throated gray warbler	–	↓	–
Green-tailed towhee	–	↑	–
Sagebrush sparrow	–	–	↓
Dark-eyed junco	–	↓	–
Black-headed grosbeak	↓	↑	–
Western meadowlark	–	↓	–
Brown-headed cowbird	↓	–	–
House finch	↓	–	–

Pinyon-juniper showed the largest number of decreasing significant trends (8), followed by the low-elevation riparian (6) and sagebrush shrubland habitats (2). Only five increasing significant trends were seen: one in low-elevation riparian habitat, and two each in pinyon-juniper and sagebrush shrubland.

Five new species were detected for this monitoring program: a sora (Porzana carolina) in Arches National Park, a bald eagle (Haliaeetus leucocephalus) in Curecanti National Recreation Area, a northern saw-whet owl (Aegolius acadicus) and a purple martin (Progne subis) in Dinosaur National Monument (NM), and an American redstart (Setophaga ruticilla) in Canyonlands National Park.

Northern saw-whet owl is listed as “present” on Dinosaur National Monument’s NPSpecies list, while purple martin is listed as “unconfirmed.” According to records from ebird (ebird.org, the world’s largest biodiversity-related citizen science program), there are only two confirmed submissions of northern saw-whet owl detections and no previous confirmed detections of purple martin. American redstart is not included on the NPSpecies list for Canyonlands National Park, and has not been confirmed as detected in ebird records for the park, making this the first record of this species in this park.

A total of 115 individuals of 30 species were recorded in Pipe Spring NM in 2018. Sample sizes were too low for estimation of density trends.

How is this Information Used?

In order to know which species to manage for, park managers need to know which species are present. Data from this monitoring is also useful for park planning documents, such as Natural Resource Condition Assessments and State of the Park reports, and demonstrates 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, Black Canyon of the Gunnison, Bryce Canyon, Canyonlands, Capitol Reef, and Zion national parks; Colorado, Dinosaur, Fossil Butte, Natural Bridges, and Pipe Spring national monuments; and Curecanti National Recreation Area.

The results in this article were summarized from S. G. Roberts, E. L. Tymkiw, Z. S. Ladin, and W. G. Shriver. 2020. Landbird monitoring in the Northern Colorado Plateau Network: 2019 field season.

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