Birds

Breeding Birds

Many songbird species that nest in eastern forests are in decline. Logging and forest care may cause part of this decline, but smart forest management can also help save these birds. Since the Hardwood Ecosystem Experiment (HEE) began, field workers led by Dr. John Dunning have counted breeding birds across the test sites. These counts show where birds live, how many there are, and how bird groups change when trees are cut.

Ever since the first timber harvests, researchers have tracked bird responses on both small cut sites and across larger forest areas. Field workers do 10-minute counts at fixed spots, recording every bird seen or heard within 100 meters.

Several researchers have led specific parts of this work. Melissa Malloy looked at quick changes in common songbird areas during the first few years after logging. Dr. Patrick Ruhl and Dr. Ken Kellner studied longer-term effects on where birds live and how well they raise their young. Although workers count all bird species, some need extra protection. These special birds include migratory songbirds like the Wood Thrush and Scarlet Tanager, local birds like Blue Jays that eat nest eggs and spread acorns, and rare birds like wintering Golden Eagles and steep-slope Worm-eating Warblers.

Surprisingly, Worm-eating Warblers became one of the most common birds caught in clearcut areas years later, once dense young shrubs and trees grew back. Dr. Ruhl focused his research on how these young growth patches help birds, which included banding local warblers over many years.

Key Papers:

Cerulean Warbler

Project Investigator
Kamal Islam (Retired), Ball State University, (765) 285-8847, kislam@bsu.edu

Dr. Kamal Islam and his students have studied the endangered Cerulean Warbler in southern Indiana since 2000. This tiny songbird flies south for winter, but its numbers on northern breeding grounds have dropped for over 45 years. Researchers want to find out what is causing this decline in Indiana.

Cerulean Warblers mostly live in old forests, but they like gaps in the high tree canopy. Small cut openings made by foresters attract them, which shows that canopy gaps are a key habitat need. The main goals for this project are to track bird numbers across different logging styles, measure how many chicks survive, and compare bug levels on oak and hickory trees to see how food affects adult and chick health.

The team recently added radio tags to track young chicks that just left the nest. Studies show that young birds from old forests often move into young forest growth created by tree harvests. Results from this study will help land managers protect this rare species.

Key Papers:

• Ruhl, P.J., Kellner, K. F., and J.B. Dunning. 2020. Ecological factors explain habitat associations of mature-forest songbirds in regenerating forest clearcuts. The Wilson Journal of Ornithology doi: https://doi.org/10.1676/19-49
• Kellner, K.F., Ruhl, P.J., Dunning, J.B., Barnes, K.W., Saunders, M.R., and R.K. Swihart. 2018. Local-scale habitat components driving bird abundance in eastern deciduous forests. The American Midland Naturalist, 180(1):52-65.
• Ruhl, P.J., Delancey, C.D., and J.B. Dunning Jr. 2018. Roost preference, post-fledging habitat use, and breeding phenology of adult female Worm-eating Warblers (Helmitheros vermivorum) on the breeding grounds. The Wilson Journal of Ornithology., 130(2): 397-409.
• Kellner, K.F., P.J.Ruhl, J.B.Dunning, J.K.Riegel and R.K.Swihart. 2016. Multi-scale responses of breeding birds to experimental forest management in Indiana. Forest Ecology and Management, 382:64-75.

Nightjars / ARUs

Project Investigator
Brent Pease, Southern Illinois University, bpease1@siu.edu

Getting accurate animal counts across big forest areas is a key goal for wildlife conservation. Over the past ten years, passive recorder setups have become popular because they save money, record for long times, and store audio for later study. However, using sound clips to count exact bird numbers is still hard due to background noise, double-counting, and judging how far away a bird is singing.

Eastern Whip-poor-wills are night birds that catch flying insects. Because they have very clear calls, they are great test subjects for acoustic recording research, though clear field rules are still needed. Whip-poor-wills are at risk in Indiana and across the nation, yet we still know very little about how logging affects them.

To test these recording devices across the project area, researchers set up acoustic units across all nine sites from mid-May to mid-July. Devices record for four hours near sunrise for songbirds and four hours after sunset for night birds. Field workers also do in-person night counts to compare human bird counts against device recordings. The main goals of this work are to test ways to estimate Whip-poor-will numbers using audio recorders and to see how different logging methods affect bird counts over time.

Density estimation with ARUs | PEASE Lab