Design and construction of mourning dove research pens.

Millspaugh, Joshua J.

Abstract: To assist with mourning dove (Zenaida macroura) research, we designed and built 69 outdoor cages. The cages were flexible in meeting our data collection protocols, and the biological needs of captive wild mourning doves. The basic outside dimensions of the cage were 244 cm high, 183 cm wide, and 183 cm deep with the cage floor 61 cm off the ground, and covered with a corrugated steel roof. The number of different length boards and tools were kept to a minimum to simplify construction. The cages were constructed in 5 weeks with 3 full-time employees (40 hr/week), with incidental assistance from 3 other people. Cost of materials in 2001 for each cage was [less than or equal to] $220, including the cost of wood, roofing, wire, and hardware. With minor modifications, the cage design permits research opportunities for a wide range of other avian species to gain knowledge about research techniques and associated ecosystem processes.

Key Words: cage design, Missouri, mourning doves, Zenaida macroura

Introduction

Mourning doves (Zenaida macroura) are the most studied and heavily hunted migratory upland game bird in North America (Baskett et al. 1993, Mirarchi and Baskett 1994, Tomlinson et al. 1994). Despite extensive and voluminous information, few data exist concerning fundamental management and research questions. For example, why are mourning doves experiencing long-term population trend declines in the Eastern, Central, and Western Management Units as measured by the National Call-Count Survey (Dolton et al. 2001)? Answers to this daunting wildlife management question will involve a series of research projects using a variety of research techniques; e.g., trapping and marking individual birds with leg bands, patagial wing tags, and/or radio transmitters.

Until recently, few biologists have considered the potential negative effects of wildlife research techniques, and the impacts those effects may have on the resulting data and related management decisions. One of the most problematic issues affecting mourning dove research is determining the effects of attaching and carrying radio transmitters (Schulz and Sheriff 1995). Using relatively small stainless steel cages (24 x 18 x 18 cm) and 200 wild mourning doves kept in captivity, subcutaneously implanted radio transmitters with external antennas were shown to be a preferred attachment alternative to intra-abdominal implants with external antennas (Schulz et al. 1998). Using slightly larger stainless steel cages (24 x 40 x 18 cm) and 195 wild captive mourning doves, subcutaneous radio transmitter implants with external antennas were shown to be a superior to glue attachment based on retention time, and superior to harnesses based on pathological effects (Schulz et al. 2001). Although the size of the cages used in these previous studies were considered within acceptable research guidelines (Mirarchi 1993, Gaunt and Oring 1997), the cages were not large enough to allow the birds to fly; thus, further evaluations must be conducted in larger outdoor pens that simultaneously allow the individual birds to fly while still conducting experiments with relatively large sample sizes of birds. Size, shape, and the number of the outdoor cages are dependent upon the needs of the birds, experimental data collection protocols, cost of materials, and ease of construction. Although several depictions of cages used for mourning dove research have been published (Hanson and Kossack 1963, Mirarchi 1993), they do not provide details on construction or materials. Our objective, therefore, was to design and construct [greater than or equal to] 60 outdoor cages for mourning dove research that would accommodate data collection protocols, would be easily produced, and provide flexibility in meeting the biological needs of captive wild mourni ng doves. Other avian researchers may find this design useful because it allows flexibility in the type of experiments to be conducted (e.g., studying transmitter effects, understanding patterns in stress hormones, and disease/toxicity testing), and can be used with other avian species with minor modifications.

Cage Design and Construction

To economize labor and simplify construction, we divided the cage construction process into the following steps: cutting lumber, framing cages, cutting wire, attaching wire, attaching roofing, and building/attaching doors. We used pressure-treated chromated copper arsenate (CCA) lumber which resists termites and fungal decay to ensure that the cages would last for several years. When handling the CCA lumber, we followed recommended personal safety guidelines (Material Safety Data Sheet: Product Type, Wolmanized[R] Treated Wood and Lumber, June 19, 2000; 4 pp). We also kept the number of different length boards to a minimum to reduce the amount of cutting (Table 1). We used 3 x 5 cm welded wire (183 cm wide in 30 m rolls), and 244 x 91 cm galvanized metal roof sheathing. A minimum of hand and power tools were needed to complete pen construction; e.g., wire cutter, electric chop-saw, reciprocating power saw, battery-powered electric drills, and a pneumatic stapler. The basic outside dimensions of the cage were 244 cm high, 183 cm wide, and 183 cm deep with the cage floor 61 cm off the ground, and covered with corrugated steel; the basic size allowed us to use commercially available materials with little waste. Each cage had two doors; one smaller bottom door for daily feeding and watering, and a larger upper door for cage cleaning (Figure 1). Approximately 28 CCA 4 x 9 x 244 cm boards were needed per pen with an estimated 2001 cost of [less than or equal to] $220, including the cost metal roofing and wire; shorter pieces of wood (e.g., corner braces) were made from scrap materials (Table 1).

To speed construction, we precut all wood prior to cage assembly (Table 1). Using 6 cm #8 galvanized wood screws, we screwed together two 4 x 9 x 244 cm boards lengthwise to form the cage legs. Next, we framed the basic structure by assembling the two sides of the cage by attaching a 173 cm board across the top of two legs, and another 61 cm from the bottom. We stood the two sides upright, and attached 4 additional 173 cm boards at the top and 61 cm from the bottom to complete the basic square cage frame. To increase the rigidity of the cage, we attached comer braces with 450 cut ends to the inside corners at the top and bottom of the cage. Perpendicular to the cage floor side rails, we attached two 173 cm pieces to provide a stable substrate for the wire cage floor. We attached two additional 173 cm pieces across the top of the cage to provide a surface for roof attachment. Next, we attached 173 cm boards to the outside of the cage frame to provide a flat surface for attaching the welded wire.

The cage floor was built using 2 layers of 3 x 5 cm welded wire separated by the 4 x 9 cm floor braces; the two wire mesh layers reduced the likelihood of predation. First, we tipped the cages over on their sides so we could attach the bottom layer of wire using the pneumatic staple gun. Next, we flipped the cages upright and attached the top layer of wire to the cage floor. After attaching the double cage floor, we attached the pre-cut wire cage to the three sides without doors. We attached the large wire panels by first stapling the center of panel to cage, and then moved towards the edges; this reduced sagging of the wire. We next attached the corrugated metal roofing using galvanized self-tapping roofing screws. The metal roofing was attached to provide approximately 30 cm of overhang on the front and back of the cage, and to fit flush on both sides.

The last step in constructing the cages was to build and attach the doors; much of the material for the doors was obtained from left over scraps. The CCA scrap 4 x 9 cm boards were cut longitudinally (or ripped) on a table saw so that the entire door was made from 4 x 4 cm wood. The smaller bottom door was 61 x 61 cm, and constructed of 2 pieces of wood 61 cm (top and bottom of door) and 2 pieces 53 cm (sides of door; Figure 1). The larger upper door was constructed of 2 pieces of 61 cm (top and bottom of door) and 2 pieces 112 cm (sides of door; Figure 1). After the upper and lower doors were framed, we attached 30 cm corner braces cut with 450 angles on the ends; this provided a stronger door frame and more surface area for attached the wire on the door. Next, we attached pre-cut panels of wire to the doors with the pneumatic stapler. The last step was to attach the doors to the cage with hinges and locking hasps. Once completed, we provided poultry watering jugs and food trays in each cage and used scrap w ood placed through the upper cage corners to provide aerial roosting (Figure 1).

Results and Discussion

We built 69 cages in 5 weeks with 3 full-time employees (40 hr/week) and incidental assistance from 3 other people. By creating a simple design that took advantage of commercially available material in standard sizes, we were able to use a minimum of supplies with little waste. Sixty of the cages were placed in 10 rows of 6 cages to provide a facility for experimental research using captive wild mourning doves; 9 other cages were constructed to provide space for stock-piling birds for future research. Our experience indicates the cages provide ample room for individual birds to conduct normal activities (e.g., flying, roosting, feeding), while simultaneously confining the birds in a small enough space to ensure easy capture and collection of necessary data. The cages also provided a setting where newly captured wild mourning doves can be kept with other doves to acclimate to captivity.

Although these cages were designed and used for mourning dove research, the 60 cage facility can provide research opportunities for other species. For example, we used our cages without any modification for pilot experiments dealing with Northern bobwhites (Colinus virginianus), Northern cardinals (Cardinalis cardinalis), and Eastern cottontail rabbits (Sylvilagus floridanus). This adaptability is important because there are numerous future opportunities to conduct experimental research on a whole suite of captive wild birds to gain knowledge about research techniques and their asssociated ecosystem processes.

Table 1

Construction materials and cost of supplies needed to make one mourning
dove cage

Material Number Length of Price of
 of Pieces Each Peice (1) All Pieces

CCA Wood (4 x 9 x 244 cm
@ $2.45 apiece)

 8 244 $19.60
 12 173 $29.40
 6 163 $14.70
 2 81 $2.45
 1 183 $2.45
 8 30 (scrap wood)

Wire (3 x 5 cm mesh; 183 x
3048 cm rolls @ $1.60/30 cm

 1006 $52.80

Metal Roofing (91 x 244
cm @ $10.00/sheet)

 2 244 $20.00

Galvanized screws and staples $30.00
for pneumatic stapler

Hinges, hasps, and $45.00
miscellaneous

Total Cost $216.40

(1) Lengths measured in cm.

Acknowledgments

We thank those individuals who helped with construction of the pens during hot and humid weather; B. Crampton, T. Hinkleman, S. Kistner, C. Rittenhouse, and B. Washburn. Funding for this study was provided by 2001 Webless Migratory Game Bird Research Program (United States Fish and Wildlife Service and the United States Geological Survey-Biological Resources Division), the University of Missouri (Department of Fisheries and Wildlife Sciences), and the Missouri Department of Conservation Research Center (Federal Aid in Wildlife Restoration Project W-13-R).

Literature Cited

Baskett, T. S., M. W. Sayre, R. E. Tomlinson, and R. E. Mirarchi, editors. 1993. Ecology and management of the mourning dove. Stackpole Books, Harrisburg Pennsylvania, USA.

Dolton, D. D., Holmes, R. D., and G. W. Smith. 2001. Mourning dove breeding population status, 2001. U.S. Fish and Wildlife Service, Laurel, Maryland, USA.

Gaunt, A. S., and L. W. Oring, editors. 1997. Guidelines to the use of wild birds in research. The Ornithological Council Special Publication, Washington D.C., USA.

Hanson, H. C., and C. W. Kossack. 1963. The mourning dove in Illinois. Illinois Department of Conservation Technical Bulletin 2, Southern Illinois University Press, Carbondale, USA.

Mirarchi, R. E. 1993. Care and propagation of captive mourning doves. Pages 409-428 in T. S. Baskett, M. W. Sayre, R. E. Tomlinson, and R. E. Mirarchi, editors. Ecology and management of the mourning dove. Wildlife Management Institute, Washington, D.C., USA.

Mirarchi, R. E., and T. S. Baskett. 1994. Mourning dove (Zenaida macroura). The birds of North America, number 117. The American Ornithologists' Union, Washington, D.C., USA, and The Academy of Natural Sciences, Philadelphia, Pennsylvania, USA.

Schulz, J. H., and S. L. Sheriff. 1995. Evaluation of field techniques for estimating population parameters for mourning doves in central Missouri. Missouri Department of Conservation, Federal Aid in Wildlife Restoration Project W-13-R-49, Final Report.

Schulz, J. H., A. J. Bermudez, J. L. Tomlinson, J. D. Firman, and Z. He. 1998. Effects of implanted radiotransmitters on captive mourning doves. Journal of Wildlife Management 62: 1451-1460.

Schulz, J. H., A. J. Bermudez, J. L. Tomlinson, J. D. Firman, and Z. He. 2001. Comparison of radiotransmitter attachment techniques with captive mourning doves. Wildlife Society Bulletin 29:771-782.

Tomlinson, R. E., D. D. Dolton, R. R. George, and R. E. Mirarchi. 1994. Mourning dove. Pages 5-26 in T. C. Tacha and C. E. Braun, editors. Migratory shore and upland game bird management in North America. International Association of Fish and Wildlife Agencies, Washington, D.C., USA.