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2000 SUMMARY OF RED-SHOULDERED HAWK
REPRODUCTION IN NORTHEASTERN AND CENTRAL WISCONSIN
An unpublished annual report for:
U.S. Fish and Wildlife Service
Wisconsin Department of Natural Resources-Bureau of Endangered Resources
U.S. Forest Service, Chequamegon-Nicolet National Forest
Northeastern Wisconsin Audubon Society
BY
JOHN JACOBS
NEVILLE PUBLIC MUSEUM, 210 MUSEUM PLACE,
GREEN BAY, WI 54303
and
EUGENE JACOBS
LINWOOD SPRINGS RESEARCH STAnON
1601 BROWN DEER LANE,
STEVENS POINT, WI 54481
©
John and Eugene Jacobs 9/30/00
BACKGROUND AND METHODS
The red-shouldered hawk (Buteo lineatus) is a medium size woodland hawk that was
widespread and once one of the most common hawks in eastern United States. This hawk now
is much reduced in the northern part of its range (Peterson, et al. 1992). In the north central
states, red-shoulders are still declining, or stable at a very low population size (Peterson, et al.
1992). This is a species that depends on large stands of mature hardwoods, wetland woods or
mixed hardwoods and conifers. To maintain red-shoulders will require comprehensive forest
management planning. Research on the status, productivity and responses to various management
practices is needed (Peterson, et al. 1992).
Red-shouldered hawks (RS) are listed as endangered, threatened, rare, or of special
concern in 13 states. They are a threatened species in Wisconsin and there is a need for data on
their population dynamics and habitat management. In 1971 we began monitoring red-shouldered
hawk nests, studying their basic nesting ecology and population dynamics. We started with only
a few nests but now have over 150 nest sites. We are only able to check about 120 sites each
year because of time and financial constraints. Approximately 55 active nests are found each
year.
Nest sites which were active in previous years, areas where red-shoulders have been seen
or heard, and suitable habitat are searched for active nests during April and May. For most sites
we search at least a 200 meter radius around the formerly used nest. Young red-shoulders are
banded in the nest during June by climbing the nest trees. Field methods are similar to what
has been described in the literature (Craighead and Craighead 1956, and Pendleton et al. 1987).
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RESULTS AND DISCUSSION
TABLE 1
RED-SHOULDERED HAWK REPRODUCTION 2000
# OF RS SITES CHECKED
Previously active sites
New sites
# OCCUPIED SITES
# OF ACTIVE NESTS FOUND
# OF NESTS SUCCESSFUL
% OF NESTS SUCCESSFUL
# OF YOUNG FLEDGED
YG/ACTIVE NEST
YG/SUCCESSFUL NEST
(BROOD SIZE)
NNF
S.& E. OF NNF
CENWI
TOTAL
57
57
0
25
18
7
39%
13
.72
1.86
33
32
1
23
16
10
63%
20
1.25
2.00
31
31
0
25
17 (16*)
121
120
1
73
51 (~
28
55%
54
1.06
1.93
11
65%
21*
1.31
2.10
NNF = NICOLET NATIONAL FOREST
S.& E. OF NNF = NE WI: Door, Brown, S. Oconto and Marinette Counties
CEN WI = Wood and Portage Counties
* The number of young fledged was not determined for one nest, calculations were done using
21 yg for 16 nests. This also affected the totals.
TABLE 1 PRESENTS NESTING DATA FOR RSH IN WISCONSIN FOR 2000
# of RS sites checked is the forested habitat where red-shouldered hawks were
probably/possibly nesting, RS had nested previously at 120 of these sites. Only one new Site
was searched this year.
# Occupied Sites are sites in which RSH were seen or heard or had a nest fixed. Active
Nests are nests which had eggs laid in them, determined by the presence of an adult on the nest
incubating or down feathers on the edge of the nest. Successful nests produced young to the
fledgling stage. Yg/active nest is the number of young divided by the number of active nests.
We feel this is the most accurate way of determining reproductive success for hawks.
Yg/successful nest is the number of young divided by the number of nests that were successful,
this tells the average brood size. For Central Wisconsin the number of young fledged was not
determined for one nest, calculations were done using 21 yg. for 16 nests.
REPRODUCTION WAS LOWER IN YEAR 2000
Total reproduction for Wisconsin in 2000 was not real good and below the 1.4 yg/active nest
we calculated is needed for replacement of adults in the population.
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One adult female was retrapped for a third time at the same site she was originally banded
as an adult in 1985, this makes her at least 17 yrs. old (record age for a wild RS is 20 yrs).
We were able to determine age, second year (SY brown plumage) or after second year
(ASY orange breast, black and white wings and tail) for 47 male and female breeding redshoulders. All were in adult plumage. In 1999, 2 (4 %) breeding red-shoulders were in juvenile
plumage (second year). We expected a few juvenile breeders again this year because of the good
reproduction last year. Six per cent of the breeding RS were SYs in 1998. We had no SY
breeders in 1997. Our average for 1995-96 is 3.5 %. The percent of red-shoulders breeding in
juvenile plumage varied in other studies: 0% Craigheads 1956, .7% Henny et al. 1973,4.5 %
Apanius 1977, and 5 % Wiley 1975. Juvenile breeders might be an indication that there are not
enough adults to fill all the available territories.
Sheet metal without grease was put on seven nest trees to protect the eggs, nestlings and
adults from mammals such as fisher and raccoon. Six of these nests produced young, an 86%
success rate.
TABLE 2
RED-SHOULDERED HAWK REPRODUCTION 1991-2000
1991
IF RS SITES CHECKED
CCUPIED SITES
# OF ACTIVE NESTS FOUND
# OF NESTS SUCCESSFUL
% OF NESTS SUCCESSFUL
# OF YOUNO FLEDGED
YGI ACTIVE NEST
YO/SUCCESSFUL NEST
(BROOD SIZE)
1992
1993
1994
1995
1996
114
148
105
119
74
72
67
83
56
58
60
51
56
55
27
19
25
28
18
30
54% 47% 32% 49% 50% 33%
47
52
41
61
35
68
1.21
.90
.86
.68 1.20
.64
2.27 1.93 2.16 2.44 1.74 1.94
107
106
10 YR.
AVE.
1997
1998
1999
2000
150
82
58
39
67%
95
1.64
2.44
130
61
51
32
63%
77
1.51
2.41
110
68
57
33
58%
82
1.44
2.49
121
121
73
73
51
56
28
28
55% 51 %
55*
61
1.06 1.11
1.93 2.18
* 55* young fledged, modified from Table 1 to reflect one nest where # of yg fledged was not determined.
TABLE 2 Shows that reproduction in 2000 was lower than our 10 yr. average.
Although higher than four years in the '90's, Wisconsin RSH in 2000 did not reproduced
well enough to replace annual mortality, according to our model. We analyzed our data for '00
using a computer population model (PD: Population dynamics modeling, version 4.0 (C) 1989
by J.W. Grier, Zoology Dept., N.D. State Univ., Fargo, ND). This modeling showed that a
population of 500 RSH would decrease over 15 years at the rate of reproduction we found for
2000. _ We used mortality rates of 57% for 1st year hawks and 25% for 2nd year and older.
Only three years in the 90's ('97, '98, and '99) had a reproductive rate high enough to replace
annual mortality.
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TABLE 3
COMPARISON OF RED-SHOULDERED HAWK REPRODUCTION FOR
WISCONSIN TO TWELVE OTHER STUDIES
SOURCE OR
RESEARCHER
# OF NESTS, LOCATION, YEARS
NUMBER OF YOUNG
PER ACTIVE NEST
51 NE & C WISCONSIN 2000 (range .72-1.31)
JACOBS
JACOBS
557 NE & C WISCONSIN 1990-99 (range .36-2.00)
EBBERS
73 N LOWER MICHIGAN 1986-88 (range 1.1-2.7)
CRAIGHEADS
61 S LOWER MICHIGAN 1942,47,48 (range 1.7-1.9)
STRAYERS
60 IOWA & SW WISCONSIN 1983-94 (range .45-2.04)
BEDNARZ
8 IOWA
1979
DIJAK ET AL.
34 MISSOURI
1982-83
CROCOLL ***
9 W NEW YORK
1989
JOHNSON
39 C NEW YORK
1989
6 S ONTARIO
1982
ARMSTRONG +
1982
JANIK & MOSHER 17 W MARYLAND
STEWART
52 MARYLAND
1947
WILEY
29 CALIFORNIA
1973
HENNY
74 MARYLAND 1943,49,60-71 (range .50-3.33**)
HENNY'S RECRUITMENT RATE REVISED
(HENNY ET AL. 1973)
JACOBS' RECRUITMENT RATE
1.06
1.13
1.60
1.80
1.52
*2.90
1.79
1.10
1.40
1.80
1.80
* 2.54
1.34
1.58
1.95
lAO
* these are the only two studies in which reproduction exceeded Henny's Recruitment Rate
** large variation in range is due to small sample size of 6 nests/year
*** CROCOLL & PARKER
+ ARMSTRONG & EULER
TABLE 3, WISCONSIN PRODUCTIVITY IS MUCH LOWER THAN OTHER STATES
Table 3 compares our 2000 reproduction data to studies from other states, to Henny's
recruitment rate, and our own recruitment rate based on Grier's population model mentioned
earlier. It's obvious that we have averaged very low reproduction, even our 2000 rate is much
lower than other studies. We are concerned about the low reproduction in Wisconsin and have
made recommendations in previous reports, below and in Appendix 1.
Only two of the studies, Stewart's and Bednarz's, exceeded Henny's recruitment rate, but
almost all exceeded our recruitment rate. Therefore, we think our rate is more reasonable, and
might even be too high. Other studies stated that Henny's data was biased and his rates were
probably too high (Newton 1979).
Wide variations in reproduction was reported not only between studies but within the
same study, from year to year (Henny, Stravers, Jacobs) and between areas within the same state
(Ebbers, Jacobs). Studies with small sample size had the largest ranges showing the value of
large sample sizes and long term ongoing studies.
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RS Callback Surveys in Wisconsin
Most of the potential/probable RSH habitat in Brown and Door counties were surveyed during
the springs of 1996-99 by Mike Grimm and Chris Danou of the Nature Conservancy and Mary
Standish, Andy Dyer and John Jacobs. Conspecific calls were broadcasted at designated sites under
good weather conditions.
RECOMMENDATIONS
HABITAT AND NEST SITES NEED PROTECTION
Habitat management plans for rare, threatened and endangered species should have the highest
priority, not the lowest, in the overall management of our forests. From our studies in Wisconsin,
we are convinced habitat, especially nesting habitat for red-shoulders needs to be preserved· or at
least carefully managed or red-shoulder populations will decline. Studies in other states show
habitat destruction has been recognized as the main cause for low red-shoulder populations (Peterson
et al. 1992). Present management plans and forestry methods on county and state forests do not
protect red-shouldered hawk nest sites or habitat, even though it is a threatened species. Please see
Appendix 1 for general and specific recommendations for managing RSH habitat.
CONTROL FISHER AND RACCOON POPULAnONS
Fisher are common and expanding their population. Raccoons are extremely common. They
both are killing a lot of nesting hawks. Since fur prices are so low, increasing trapping quotas on
fisher probably will not control their population, but we suggest it anyway. Some kind of fisher
control is needed for the next few years until their population stabilizes. Raccoon numbers have
been high the last 10 years or more. Without trapping, about the only limiting factors to raccoon
numbers are road kills and disease.
ACKNOWLEDGEMENTS
We sincerely thank the following people for their assistance with the red-shouldered hawk
project in 2000: Elaine Friedrick, Mary, David and Greg Jacobs helped with field work and sherpa
duties in NE Wisconsin. Elaine Friedrick, Joan Berkopec, Ron Eichhorn, and Ed Smith helped with
field work in Door County. Adam Ryba, Dennis Haessly, Kody Kuehn and Dave Noble helped with
field work in Central Wisconsin. Tom Erdman reported several active nests. Personnel with the
U.S. Forest Service, Chequamegon-Nicolet National Forest: Norm Weiland, Gary Zimmer, Tom
Mathia, and Mike Peczynski helped coordinate efforts on their districts.
Sumner Matteson,
Wisconsin Department of Natural Resources-Bureau of Endangered Resources helped secure funding.
We especially thank our wives and families for their support and patience on a project that, for them,
seems to never end.
FINANCIAL SUPPORT
Major financial support for this year's research came from: Wisconsin Department of Natural
Resources-Bureau of Endangered Resources, U.S. Forest Service Chequamegon-Nicolet National
Forest, and Northeastern Wisconsin Audubon Society.
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LITERATURE CITED
Aparuus, V., 1977. RED-8HOULDERED HAWKS IN lUVENILE PLUMAGE NEST SUCCESSFULLY. Auk 94:585.
Armstroog,E.,& D. Euler. 1983. HABITAT USAGE OF TWO WOODLAND BUTEO SPECIES IN CENTRAL ONTAR[O. Canadian Field-Nat. 97:200-207.
Bednarz, I.C. 1979. PRODUCTIVITY, NEST SITES, AND HABITAT OF RED-8HOULDERED AND RED-TAlLED HAWKS IN IOWA. Master's thesis, Iowa State Uoiv., Ames.
Bent, A.C., 1937. LJFE HlSTORIES OF NORTH AMERICAN BIRDS OF PREY, Part 1. Smithsonian Institution United States National Museum, Bulletin 167.
Oapp, R.B., Kli.mkiewicz, M.K., Kennard, J.H., 1982. LONGEVITY RECORDS OF NORTH AMERICAN BIRDS: GAVlIDAE THROUGH ALCIDAE. JOW'. Field Orni. 53:81-124
Craighead, J.J. & Craigbead, F. C. Jr., 1956. HAWKS, OWLS AND WILDLJFE. The SlaC!q>ole Company and the Wildlife Management Institute.
Crocoll, S.T.& 1.W. pmer. 1989. THE BREEDINO BIOLOGY OF BROAD-WINGED AND RED-SHOULDERED HAWKS IN WESTERN NEW YORK. lour. Raptoc Resr.23: 125-139.
,
Curtis, 1.T., [959. THE VEGETATION OF WISCONSIN. The University of Wisconsin Press, Madison.
Dijak, W,D., Tanoenbaum B., & Pmer, M.A., 1990.NEST-8ITE CHARACTERISTICS AFFECTING SUCCESS AND REUSE OF RED-SHOULDERED HAWK NESTS.
Wilson Bull.102:48Q-486.
Ebbers, B.C., 1989. RELATIONSHIPS BETWEEN RED-SHOULDERED HAWK REPRODUCTION AND THE ENVIRONMENT IN NORTHERN MlCHIGAN. Unpub. rep. Mich, DNR.
Henny, C.l., 1972. ANALYSJS OF POPULATION DYNAMICS OF SELECTED AVlAN SPECIES WITH SPECIAL REFERENCE TO CHANGES DURING THE MODERN PESTICLDE ERA.
U.S. Bur. Sport Fish. Wildl. Res. Rep. [. Washington D.C. 99pp.
Henny, C.l., Scbmid, F.C., Martin, E.L., & Hood, L.L., 1973. TERRITORIAL BEHAVIOR, PESTICIDES, AND THE POPULATION ECOLOGY OF RIlD-8HOULDERED HAWKS IN
CENTRAL MARYLAND, 1943-1971. Ecology 54:545-54.
lanik, C.A.,& 1.A. Mosher. [982. BREEDING BIOLOGY OF RAPTORS IN THE CENTRAL APPALACHIANS. JOW'. Raptor Rest. 16: 18-24.
Johnson, G. 1989. STATUS AND BREEDING ECOLOGY OF THE RED-SHOULDERED HAWK IN NORTH CENTRAL NEW YORK. Master's thesis, State Univ. of New Yock, Syracuse.
Newton, I., [979 . POPULATION ECOLOGY OF RAPTORS. Buteo!look.'l, Vermillion, South Dakota.
Pendleton, B.A.G., Millsap, B.A., Oine, K.W., Bird, D.M., 1987. RAPTOR MANAGEMENT TECHNIQUES MANUAL. SCientific and Technical Series No. 10, National Wildlife Federation.
Peterson, 1.M., Crocoll, S.T., & Soule 1.'0., 1992. ELEMENT STEWARDSHIP ABSTRACT FOR BUTEO LINEA11JS, RED-8HOULDERED HAWK. Puh. by The Nature ConseNancy.
Stewart, R.E., 1949. ECOLOGY OF A NESTING RED-SHOULDERED HAWK POPULATION. Wilson Bull. 61:26-35
Strayers, 1. W., K.1. McKay, E. Nelson. 1995. RED-SHOULDERED HAWK REPRODUCTIVE SUCCESS WITHlN POOLS 9-11 OF THE UPPER MJSSISSIPPI RIVER, 1983-94.
Abstract in Jour. Raptor Resr,29:67
Wiley, 1.W., [975. THE NESTJNG AND REPRODUCTIVE SUCCESS OF RED-TAlLED HAWKS AND RED-8HOULDERED HAWKS IN ORANGE COUNTY, CALIFORNIA, 1973.
Tbe Coodor 77: 133-139.
APPENDIX 1
MANAGEMENT
GUIDELINES
FOR
RED-SHOULDERED
HAWKS
AN ECOLOGICAL APPROACH
All government agencies and private industries managing forests, especially the DNR,
need to drastically change their basic concept of forestry management. Instead of a "maximum
timber harvest" or a "game species" management policy, we need a holistic ecological
management approach, one which considers all the plant and animal species in the forest
community.
An ecological management approach would maintain, recreate and encourage those native
forest communities that were present in Wisconsin 200 years ago, such as those described by
John Curtis in THE VEGETAnON OF WISCONSIN. These are the plants and animals which
Wisconsin's climate, topography, soil, etc., will support best over the long term.
We are not suggesting all forest should be "virgin" or "wilderness area", although there
certainly is a need for these areas also. Wisconsin's forests can be managed so that recreation,
preservation, economic and other concerns can all be addressed. But so far, ecological concerns
generally have been ignored in favor of maximizing timber harvests and game production.
Management vision has typically been so near-sighted. Many foresters are still managing like
they did 30, 40 or 50 years ago. Our natural heritage is disappearing rapidly in favor of deer,
grouse and aspen. Let's learn from our mistakes.
We need a more moderate management approach, an ecological approach. Our highest
forest management priority should be to maintain large tracts of those ecological communities
which were thriving in Wisconsin 200 years ago. At least 40% of all forests in Wisconsin
should be mature, native forest communities.
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SHORT TERM GUIDELINES FOR WOODLAND HAWKS
(The 25 Year Plan)
We need to do something now to manage habitat for red-shouldered hawks. While the
following recommendations are directed at red-shoulders, all woodland hawks will benefit from
these recommendations, as well as most plants and animals that live in mature forests. We
recommend three categories of management guidelines:
1. GENERAL HABITAT PRESERVATION MANAGEMENT GUIDELINES
How to keep enough habitat for the hawks to survive.
Red-shoulders need mature forests (50-100 yr old trees, 100-120 trees/acre, DBH =8-25")
with native species of mixed hardwoods and conifers for nesting areas.
1. 1 Maintain existing and encourage new extensive, native mature forests of mixed
hardwoods and conifer species (northern mesic, northern lowland, southern mesic, etc.,
as per Curtis, 1959).
1.2 Some ways to encourage and maintain extensive continuous native stands:
A. Do not clear cut areas larger than 40 acres; do not clear cut areas that are closer than
400 yards to another area that has been clear cut within the last 30 years.
B. Do not plant conifer monocultures like jack pine or red pine.
C. Do not cut hemlock, beech, or yellow birch.
1.3 Do not permit road construction or clear cutting within 100 yds. of a stream, lake
or other wetland.
1.4 Do not permit logging of any kind closer than 50 yds. from a stream or lake.
1.5 Fragmented woodlots smaller than 250 acres where red-shoulders have been seen or
heard during the breeding season (March-July) should not be logged at all.
Fragmented woodlot'; are woodlots that are less than 250 acres in size and/or more than
.3 miles distance from the next nearest woodlot and/or where the surrounding 2 square
miles are less than 50% wooded with 120 trees/acre> 8"DBH.
1.6 Rare, threatened and endangered species should have the highest management
priorities, not the lowest. All management guidelines/recommendations should be
mandatory on all public lands- Federal, State, and County. Strong, positive incentives
for private landowners to follow recommendations should be offered (like tax incentives).
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2. GENERAL NEST SITE PRESERVATION MANAGEMENT GUIDELINES
Most land owners, foresters, park managers, etc., do not know which hawks are present
and/or where the exact nest site is. Rarely do they have the resources to find and identify
nest sites. Recommendations are:
2.1 No human activity, such as tree marking, surveying, logging, road construction, etc.,
should take place in the forest from March 1 through July 15. Light human activity (tree
marking, etc.) can resume after June 1, but no machinery. Logging, construction, etc.,
should be done after July 15, during late summer, fall, and winter.
2.2 Nests discovered should be marked on a map and the SPECIFIC NEST SITE
PRESERVATION GUIDELINES #3.1-3.4 followed.
2.3 Timber sales and logging contracts should clearly state these guidelines on the
contract so that it is part of the contract or timber sale. Include a penalty clause.
3. SPECIFIC NEST SITE PRESERVATION GUIDELINES
Guidelines when the exact location of an active or formerly active nest site is known:
The general strategy is not to disturb the area near an active nest tree or alternate nests
(formerly used nests). Often, the same nest is used year after year, although some sites
might remain unused for several years before being reused. Leave an undisturbed area
around active and alternate nests so that as much of the area as possible is protected. A
list of nest sites should be maintained by the park manager, forester, or wildlife biologist
and the appropriate staff notified.
3.1 In heavily forested areas, where 50% or more of the surrounding area (2 sq. miles)
is forested (120 over-story trees/acre, with trees> 8" DBH), leave a minimum area of
40 acres untouched, i.e. a 220 yd. radius around the nest site and only selectively cut
(less than 30% basal area removal, 15 yr. rotation) an additional 80 acres adjacent to the
above 40 acres.
3.2 As mentioned earlier (recommendation 1.5) fragmented woodlots should not be
logged if red-shoulders are suspected or found nesting there.
3.3 Any roads (logging or general) should be constructed farther than 100 yards from
a nest and not constructed during the nesting season (March I-July 15).
3.4 Hiking trails, ORVs, ATVs, camping and other human activities should be
controlled, prohibited, discouraged, etc., within 200 yds. of a nest site, especially during
the nesting season (March I-July 15).
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