Changes in the breeding distribution of Buff-breasted Flycatchers in the southwestern United States: the role of fire suppression. Chris Kirkpatrick & Courtney J. Conway USGS Arizona Cooperative Fish and Wildlife Research Unit, University of Arizona

Pablo Leautaud

Thanks to: Field Assistants: Dominic LaRoche, Mike Schroff, Eli Rose, Kelly Bergstram, Brian Powell, and Mark Zepp Logistical Support: Natasha Kline, Don Swann (Saguaro National Park), Josh Taiz (U.S. Forest Service), Bob Peterson (University of Arizona), Shelly Danzer, and Sheridan Stone (U.S. Department of Defense) Bird Photography: Bruce Taubert and Tom Grey

Empidonax fulvifrons

Arizona New Mexico from Bowers & Dunning (1994)

from Conway and Kirkpatrick 2007

91% reduction in U.S. breeding range from Conway and Kirkpatrick 2007

99% reduction in U.S. breeding range

ArizonaNew Mexico 15% reduction in total breeding range from Bowers & Dunning (1994)

9 highest sky island mtn ranges What is current population trajectory?

TUCSON NEW MEXICO MEXICO ARIZONA 71 surveys in Huachucas & Chiricahuas 71 surveys in Huachucas & Chiricahuas

TUCSON NEW MEXICO MEXICO ARIZONA 44 surveys in 7 adjacent mt. ranges 44 surveys in 7 adjacent mt. ranges Replicated & surveys Replicated & surveys

At 200 m intervals along each survey route From April to July 3-min. passive period 3-min. broadcast period Point-count surveys

Regress year vs # BBFLs for 23 routes Regress year vs # BBFLs for 23 routes Test H o : average slope  0 Test H o : average slope  0 # BBFLs Detected

b avg = P = BBFLs have declined on 16 of 23 routes BBFLs have declined on 16 of 23 routes # BBFLs Detected

b avg = P = BBFLs have declined on 16 of 23 routes BBFLs have declined on 16 of 23 routes Carr Canyon # BBFLs Detected

What’s happened to BBFLs in the U.S.? Fire suppression implicated…

Coniferous forests in the SW historically subjected to low-severity fires ~1x/decade From Swetnam and Betancourt 2003

From Covington and Moore 1994

Increase in understory fuel loads has contributed to recent increase in frequency of wildfires in Southwest from Swetnam and Betancourt 2003 “Recent” Fires

If observed declines in BBFLs are due to decreased fire frequency, then…. 1) Recently burned forests more likely to be colonized by BBFLs 2) Survey points with BBFLs more likely to have evidence of recent fires 3) Survey points with BBFLs more likely to have evidence of more frequent fire events

If observed declines in BBFLs are due to decreased fire frequency, then…. 1) Recently burned forests more likely to be colonized by BBFLs 2) Survey points with BBFLs more likely to have evidence of recent fires 3) Survey points with BBFLs more likely to have evidence of more frequent fire events

5 recently burned survey routes no BBFLs detected 1 pair of BBFLs BBFLsdetected 5 unburned survey routes

Potential Problems: 1)Severity of fires was low 2)Sample size of survey routes was small

If observed declines in BBFLs are due to decreased fire frequency, then…. 1) Recently burned forests more likely to be colonized by BBFLs 2) Survey points with BBFLs more likely to have evidence of recent fires 3) Survey points with BBFLs more likely to have evidence of more frequent fire events

) no evidence of fire 1) low-severity surface fire 2) moderate-severity surface fire 3) high-severity surface fire 4) high-severity crown fire Modified from Ryan & Noste 1985 Burn Severity Index (5 classes):

Burn Severity Class Buff-breasted flycatchers more common in burned woodlands

Percent cover of vegetation at 4 heights differed among 5 burn-severity classes Burn-severity Class

1) Burn-severity index provides information on severity but not frequency of previous fire events Potential Problem:

If observed declines in BBFLs are due to decreased fire frequency, then…. 1) Recently burned forests more likely to be colonized by BBFLs 2) Survey points with BBFLs more likely to have evidence of recent fires 3) Survey points with BBFLs more likely to have evidence of more frequent fire events

1916 Fire 1865 Fire 1842 Fire 14 survey routes with BBFLs 14 survey routes without BBFLs

t paired = 1.8 P = Routes with BBFLs had more frequent fires with BBFLswithout BBFLs

1) not all trees scar during a fire 2) don’t know the severity of previous fires Potential Problems:

Summary of results Fire severity Fire frequency

Why didn’t BBFLs colonize our 5 recently (<10 yrs) burned survey routes? 1) recruitment and immigration insufficient? 2) low-severity burns insufficient? 3) BBFLs may require >10 years to locate and colonize burns

Why didn’t BBFLs colonize our 5 recently (<10 yrs) burned survey routes? 1) recruitment and immigration insufficient? 2) low-severity burns insufficient? 3) BBFLs colonize areas >10 yrs post- burn?

MEXICO Conducted surveys in 7 mt. ranges adjacent to Huachucas & Chiricahuas Last BBFL recorded 18 Aug We detected: 2 in in (incl. pair) in 2005

What’s driving BBFLs to re-colonize the Rincon Mountains after 89 year absence? 70% of bird survey points burned (56% burned severely) Ignition Points Burn Perimeters Ignitions and Fire History, Rincon Mountains, Saguaro National Park Mica Mt Rincon Peak Tucson

Carr Canyon < Fire

Santa Catalina Mountains Bullock Wildfire (2002) & Aspen Wildfire (2003)

Santa Catalina Mountains >90% burnedVariation in burn severity

Future work Continue monitoring BBFL populations in Arizona (and New Mexico?) Determine reproductive success to assess quality of habitat Determine status of Mexican population

For more information: Conway, C. J., and C. Kirkpatrick Effect of forest fire suppression on buff-breasted flycatchers. Journal of Wildlife Management 71: Kirkpatrick, C., C. J. Conway, and D. LaRoche Range expansion of the Buff-breasted Flycatcher (Empidonax fulvifrons) into the Rincon Mountains, Arizona. Southwestern Naturalist 52: Kirkpatrick, C., C. J. Conway, and P. B. Jones Distribution and relative abundance of forest birds in relation to burn severity in southeastern Arizona. Journal of Wildlife Management 70:

For more information: click on links to “Research”click on links to “Research” and “Past Project #8” and “Past Project #9”