Effects of forest management practices on bald eagles

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EFFECTS OF FOREST MANAGEMENT PRACTICES ON BALD EAGLES NESTING ON STATE AND PRIVATE LAND IN OREGON

By:

Frank B. Isaacs Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries

and Wildlife, Oregon State University, Corvallis, OR 97331, USA Robert G. Anthony

Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA Rod W. Krahmer Oregon Department of Forestry, Salem, OR 97310, USA Brady D. Callahan

Oregon Department of Fish and Wildlife, Corvallis, OR 97330, USA Jeff P. Peck

Oregon Department of Forestry, Molalla, OR 97038, USA

12 March 2005

TABLE OF CONTENTS

Title & Authors.................................................................................................. 1 Abstract............................................................................................................ 2 Introduction....................................................................................................... 5 Study Area........................................................................................................ 10 Methods.............................................................................................................11

Terminology........................................................................................... 11 Nest surveys ......................................................................................... 12 Oregon population: federal vs. non-federal ownership.......................... 13 Oregon population: non-federal 1979-1990 vs. non-federal 1991-2002............................................................................................ 15 The non-federal study population: FACTS data.................................... 15 The non-federal study population: 1979-1990 vs. 1991-2002........... 19 The non-federal study population: west vs. east.................................. 19 Statistical analyses................................................................................ 20 Results............................................................................................................... 21 Oregon population: federal vs. non-federal ownership.......................... 21 Oregon population: non-federal 1979-1990 vs. non-federal 1991-2002............................................................................................ 22 The non-federal study population: FACTS data.................................... 22 The non-federal study population: 1979-1990 vs. 1991-2002........... 24 The non-federal study population: west vs. east.................................. 24 Discussion..........................................................................................................26 1) What were the habitat characteristics of bald eagle nesting resource sites located on state and private forest land?..................... 26 2) What forest management activities took place within 1/2 mile (805 m) of nest trees?......................................................................... 27 3) Did the applied protection levels retain the bald eagle nesting resource site and protect it from damage?.......................................... 30 4) Did the applied protection levels affect the occupancy or productivity of nesting bald eagles?..................................................... 32 5) What were important habitat characteristics associated with successful bald eagle breeding areas in managed forests?.................. 34 Buffer zones, frequency of nest changes, and distance of moves with nest changes...................................................................... 35 Management implications and recommendations............................................. 38 Characteristics of bald eagle nesting habitat........................................ 38 Forest management activities within 800 m of non-federal nest

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trees, nest tree retention and protection, and occupancy and productivity of nesting bald eagles....................................................... 38 Frequency of nest changes, distance of moves, and buffer zones...... 39 Forest Activity Computerized Tracking System (FACTS)..................... 40 Forest Practices Rules for bald eagle nest trees................................... 40 Acknowledgments............................................................................................. 42 Literature cited................................................................................................. 43

Figure 1. Grid representing 4, approximately 1-mile square (259.0 ha) sections of land as they would appear in the Township and Range public land survey system (Loy 2001:18). Each section is divided into 16, approximately 40-acre (16.2 ha) parcels. Centers of 1/16 sections are shown by black dots. Nest tree locations are small open circles. Boundaries 800 m from nest trees are shown by large open circles.

Figure 2. Linear correlations of nesting success (a.) and productivity (b.) of bald eagles with proportion of 1/16 sections with operations within 800 m of nest trees at 53 breeding areas on non-federal land in Oregon, 1991- 2002. Dotted lines represent recovery goals (U.S. Fish and Wildlife Service 1986:27).

Table 1. Population size, nest tree use, and nesting outcome for bald eagle breeding areas on federal and non-federal land in Oregon.

Table 2. Population size and nesting outcome for bald eagle breeding areas on non-federal land in Oregon before and after Forest Protection Rules (FPRs) for bald eagle resource sites were implemented by Oregon Department of Forestry.

Table 3. Linear correlations of occupation, nesting success, and productivity with proportion of 1/16 sections with operations, and number of operations per 1/16 section within 800 m of nest trees at 53 bald eagle breeding areas on non-federal land in Oregon.

Table 4. Occupation, nest tree use, and nesting outcome at 53 bald eagle breeding areas on non-federal land in Oregon before and after Forest Protection Rules (FPRs) were implemented by Oregon Department of Forestry.

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Table 5. Occupation, nesting success, and productivity at bald eagle breeding areas on non-federal land west (n = 34) and east (n = 19) of the Cascade Mountains in Oregon, 1991-2002.

Table 6. Suggested minimum nest-tree and forest-stand requirements for bald eagle nest sites in 3 forest types in Oregon, 1979-1982. Reprint of Table 8 from: Anthony, R.G., and F.B. Isaacs. 1989. Characteristics of bald eagle nest sites in Oregon. Journal of Wildlife Management 53:148-159.

Appendix 1. History of bald eagle habitat management in Oregon, emphasizing the Oregon Department of Forestry's Forest Practices Rules.

Appendix 2. Explanation for selecting 53 out of 174 breeding areas for detailed analyses of data derived from the Forest Activities Computerized Tracking System, including nesting and forestry data for the 53 sites selected.

Appendix 2 Figure 1. Nesting and Forest Activity Computerized Tracking System (FACTS) data for 53 bald eagle breeding areas on non-federal land in Oregon. The 53 sites were chosen because they had 4 or more years of nesting history, all nest trees were on state or private land, and forestry was probably the primary activity within 800 m of nest trees.

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12 March 2005

Title Page, Abstract, & Key Words

Frank B. Isaacs Oregon Cooperative Fish and Wildlife Research Unit Oregon State University 104 Nash Hall Corvallis, OR 97331-3803 541-929-7154; FAX call for instructions; E-mail isaacsf@onid.orst.edu

RH: Forest management and bald eagles ? Isaacs et al.

Effects of forest management practices on bald eagles nesting on state and private land in Oregon

Frank B. Isaacs,1 Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA

Robert G. Anthony, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA

Rod W. Krahmer, Oregon Department of Forestry, Salem, OR 97310, USA Brady D. Callahan, Oregon Department of Fish and Wildlife, Corvallis, OR

97330, USA Jeff P. Peck, Oregon Department of Forestry, Molalla, OR 97038, USA

1 E-mail: isaacsf@onid.orst.edu

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Title Page, Abstract, & Key Words

Abstract Habitat management for bald eagles (Haliaeetus leucocephalus) nesting

in Oregon developed in response to laws enacted to counter declining populations. Thirty-seven percent of bald eagle nest trees documented in Oregon from 1971-2002 (n = 1,106) were on state or private (non-federal) land. Many were managed under U.S. Fish and Wildlife Service guidelines prior to 1991, and Oregon Department of Forestry (ODF) Forest Practices Rules (FPRs) from 1991 to 2002. We evaluated FPRs indirectly using data on bald eagle nesting outcomes for 1971-2002, and forestry operations reported in ODF's Forest Activity Computerized Tracking System (FACTS) from 19912002.

Nesting parameters for breeding areas on federal vs. non-federal land, non-federal land before vs. after FPRs were implemented, 53 selected nonfederal breeding areas before vs. after FPRs were implemented, and nonfederal breeding areas west vs. east of the crest of the Cascade Mountains were compared. For breeding areas on federal vs. non-federal land, change in number of breeding areas occupied, percent of breeding areas occupied, patterns of nest tree use, nesting success, and productivity were similar, whereas nest tree changes per year occupied was greater (P < 0.01) for breeding areas on non-federal land. For breeding areas on non-federal land before vs. after FPRs were implemented, percent of breeding areas occupied and nesting success were similar, while change in number of breeding areas

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