Survey of Breeding Secretive Marsh Birds in the Delta Region of Arkansas Progress Report: 2005

Michael J. Budd M.S. Student Arkansas Cooperative Fish and Wildlife Research Unit

David G. Krementz USGS Arkansas Cooperative Fish and Wildlife Research Unit

Introduction

The Delta Region of Arkansas was once part of a vast wetland area comprised of mostly bottomland hardwoods, as well as emergent and submergent wetlands, and prairie. Between the 1950s and the 1970s, much of this land was cleared and converted to agriculture and aquaculture facilities (King and Keeland 1999). Along with this change in land use has been an unknown change in the use of those wetlands by secretive marsh birds. The status and distribution of secretive marsh birds in Arkansas is not well known (James and Neal 1986, Karen Rowe, Arkansas Game & Fish Commission [AGFC], personal communication). Secretive marsh birds as a whole are declining with some species in steep decline (Sauer et al. 2005). Concern for the status and population trends has been raised by federal, state and local agencies. A primary objective mentioned by all biologists is a need for current distribution maps and population abundance estimates. Because recent developments in surveying secretive marsh birds have been made (Conway 2003), we decided to implement the survey methods of the National Marshbird Monitoring Program (Conway 2003) and assess the status and distribution of secretive marsh birds in the Delta of Arkansas. In addition to the survey, we hoped to determine occupancy rates (MacKenzie et al. 2002), investigate some factors that affect detecting these birds, and document their habitat use. We chose to survey in the Delta because previous work on secretive marsh birds there indicated that that region harbored many species and had good numbers in the past (Meanley 1969, 1992). A secondary goal was to assess if these monitoring goals would work operationally in the remainder of Arkansas. We recognized that if the protocol we intended to use could not work in the Delta Region, we knew that it would not work in other regions of Arkansas.

Secretive marsh birds included all species that primarily inhabit marshes (i.e., marsh- dependent species). Primary species of concern in North America included the king rail (Rallus elegans), clapper rail (Rallus longirostris), Virginia rail (Rallus limicola), sora (Porzana carolina), black rail (Laterallus jamaicensis), yellow rail (Coturnicops noveboracensis), American bittern (Botaurus lentiginosus), least bittern (Ixobrychus exilis), pied-billed grebe (Podilymbus podiceps), purple gallinule (Porphyrula martinica), and common moorhen (Gallinula chloropus). The U.S. Fish and Wildlife service has identified the American bittern as a Bird of Conservation Concern because they are relatively rare and we lack basic information on status and trends in most areas (U.S. Fish and Wildlife Service 2002, Conway 2003). The king rail is endangered in Canada and Michigan, Minnesota, Kentucky, Indiana, and Connecticut. We were also interested in any other wetland dependent birds that have recently begun occupying Arkansas, e.g., mottled duck (Anas fulvigula), fulvous whistling-duck (Dendrocygna bicolor), black- bellied whistling-duck (Dendrocygna autumnalis), wood stork (Mycteria americana), white-faced ibis (Plegadis chihi), glossy ibis (Plegadis falcinellus), and white ibis (Eudocimus albus). Data were also collected on the distribution of the yellow-crowned night heron (Nyctanassa violacea) and black-crowned night heron (Nyticorax nycticorax). The night herons are also wetland dependant and we lack data on their status and trends as well.

Our information will aid the AGFC in assessing the current status of secretive marsh birds in the Delta. This study should also allow AGFC to determine the feasibility of conducting similar studies throughout the rest of Arkansas and to assess the current status of secretive marsh birds there. Once the current status of secretive marsh birds is known, then AGFC and other agencies can develop appropriate management plans.

Methods

Field research began 16 April 2005 and ended 8 July 2005. We attempted to survey each site 15 times. These 15 surveys were separated into 3 time periods, ~20 days apart. For each survey period, we made 5 repeated visits over 1½ - 2 days. Repeating surveys in this fashion increases confirmation of seasonal presence or absence of some marsh bird species in a wetland to a 90% certainty (Gibbs and Melvin 1993).

Sites were randomly selected by overlaying a grid on GIS layers containing wetland data from the Delta. To help stratify our sampling protocol, we decided to sample large vs. small wetlands, isolated vs. contiguous wetlands, and marshes vs. swamps. Random numbers were generated and used to select the sites from the grid based on these 8 possible combinations. During our selections, we discovered that not all combinations of variables were possible. Some sites were selected if refuge managers or landowners were interested in marsh bird information for a particular wetland. Several sites were located haphazardly due to logistical problems preventing us from contacting landowners, or because designated wetlands no longer existed. In that instance, wetlands closest to the randomly selected wetland were chosen.

Surveys were conducted from ½ hour before sunrise to 2 hours after, and from 2 hours before sunset to ½ hour after. Surveys were not completed during heavy rain, heavy fog, or wind speeds >19 km/h. Breeding and territorial calls were broadcast from portable CD players and speakers to elicit a response from the birds. We recorded on each survey the marshbird species present and numbers detected. The methods used followed the National Marshbird Monitoring protocol (Conway 2003).

We collected the following habitat data within 100 meters of each survey point: 1) wetland vegetation rank based on the amount of emergent, submergent, floating, and woody vegetation, 2) wetland edge rank, 3) rank of wetlands, agriculture, pasture, forest, and shrub within 400 meters, 4) percent cover of each major plant species, 5) overall vegetation cover of each wetland was categorized, 6) distance (m) from the survey point to an irrigation ditch, 7) width and slope of the ditch, and 8) the rank of shrubs, forest, and pasture along 100 meters of the ditch. We chose variables 1-5 because they influence marshbird occupancy rates (Brown and Dinsmore 1986). Variables 6-8 were thought to influence occupancy rates of king rails (S. King, USGS Louisiana Fish & Wildl. Res. Coop Unit, personal communication). Rankings were based on percent coverage as follows: 0 = 0-10, 1 = 11-50, 2 = 51 – 90, 3 = 91 – 100.

Marshbirds were often found on adjacent wetlands (not occupying the selected site) yet still audible or visible to the observer. Several birds were also located while en route to other sites. These were recorded as opportunistic marshbird sightings (Table 2).

Results

We surveyed 80 wetlands during the 2005 season (Figs. 1-3). We surveyed 21% of the sites 15 times and 56% of the sites were surveyed ≥5 times. Wetland permanence was a major issue as the Delta experienced drought like conditions, resulting in more than half of our sites drying up before we could survey them 15 times. If sites were dry on return visits, than any wetlands found near the original site were surveyed. We did not detect any effects, positive or negative, of playing calls of other species on detection rates of any particular species. The peak number of detections for all species that we recorded occurred during the latter half of April and declined as the summer progressed (Fig.4). The only birds showing an increase in detection rates as the summer progressed were the least bittern and pied-billed grebe (Fig.5).

If a wetland contained a secretive marsh bird, we found that 81% of those wetlands had >1 bird. On average, we detected 2 marsh birds per occupied wetland. We found that about half (54%) of our surveyed sites had ≥1 species of secretive marsh bird. We detected an equal number of birds on visit 1 compared to visits 2-5.

Contacting landowners in the Delta was time consuming without the aid of plat maps. Corporate farms also leased large areas of the Delta making it difficult to gain access to the land. This winter we will attempt to contact private landowners so that we can survey more private lands during the 2006 field season.

Marshbird Accounts

We detected pied-billed grebes at 9 sites with an average of 2 individuals sighted at each wetland (Table 1).

At 14 sites we detected least bitterns, and a few least bitterns were detected on non- selected wetlands (Table 2). We encountered 9 American bitterns of which 4 were located in the same wetland at Bald Knob National Wildlife Refuge (BKNWR). These birds were very vocal and displayed throughout the day. During the second set of surveys at BKNWR, we detected no American bitterns.

We detected soras from 18 April - 22 May. Many soras were heard and seen at BKNWR in the same unit as the American bitterns. This unit was a rice field the previous year and also contained American coots, pied-billed grebes, and a Virginia rail. We detected Virginia rails at 5 sites up through 5 May. During our field research, we detected king rails at 12 sites. We did not detect any king rails in rice fields. The distribution of the king rail was widespread from north to south but all sightings were within 27.5 km of the Mississippi River (Fig. 6). We made visual sightings on >10 individuals. We only detected purple gallinules at Arkansas Post National Park (NP) and at Bayou Meto Wildlife Management Area (WMA). Common moorhens were detected at 2 sites including Arkansas Post NP which had the highest density with ~ 15 pairs observed. We opportunistically located moorhens at 2 other wetlands. American Coots were detected at 6 sites and all encounters were visuals. There were 7 opportunistic sightings of coots.

We detected mottled ducks at 12 sites. One female mottled duck was seen with 8 fledglings in Chicot County on 19 May 2005. Black-bellied whistling-ducks were found at 3 locations. The largest concentration found was west of Hamburg on Loyds bayou with ~ 9 individuals. All sightings of whistling ducks were in the southern section of the Delta.

We found White ibis at Bayou Meto WMA, Overflow NWR, and on Loyds Bayou west of Hamburg. There were ~35 individuals detected over the summer. We observed 2 white-faced ibis, 1 at BKNWR and 1 at Oakwood NWR.

We detected 2 yellow-crowned night herons at Wapanonca NWR and 5 at Black River WMA. All sightings of these birds were in bottomland hardwood wetlands. We recorded 8 black-crowned night herons at Oakwood NWR, 5 in St. Francis County, and 1 at Big Lake NWR.

We did not detect any wood storks, glossy ibis, or fulvous whistling-ducks.

Future Plans

This winter we will analyze our survey data using program PRESENCE to assess if our efforts were sufficient to allow estimation to proceed. Depending on our results, we will modify our sampling scheme accordingly. We are already planning on gaining access to more private lands to even out our sample. Should we have enough detections per species, we will conduct some pilot work on whether those species are associated with particular vegetation or landscape characteristics. Most likely, we will have to lump across guilds to have enough observations to run such analyses. Once we have finished these pilot analyses, we will revaluate our sampling plans.

Our results to data have been encouraging. We detected more species and more individuals than we had originally anticipated. With our pilot work behind us, we anticipate that we will accomplish even more next breeding season.

Fig.1. Site numbers and locations for the northern sampling area in the Arkansas Delta.

Fig. 2. Site numbers and locations for the central sampling area in the Arkansas Delta.

Fig. 3. Site numbers and locations for the southern sampling area in the Arkansas Delta.

160 140 120 100

80 60 DETECTIONS 40 20 0 APRIL 16-27 MAY 1-15 MAY 16-31 JUNE 1-16 JUNE 17-30 July 1 - 8 DATE

Fig. 4. Numbers of marshbirds detected during 2005 breeding season in the Delta of Arkansas.

16

14

12

10 LEBI 8 PBGR 6 DETECTIONS 4

2

0 April 15 - 30 May 1 - 15 May 16 - 31 June 1 - 16 June 16 - 30 July 1 - 8 DATE

Fig. 5. Detections over the breeding season for the pied-billed grebe (PBGR) and least bittern (LEBI) in the Delta of Arkansas.

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Fig. 6. Distribution of king rails in the Delta of Arkansas during the breeding season of 2005.

Table 1. Sites surveyed listing site number (see Figs. 1-3), species observed (refer to Appendix), and UTM coordinates.

SITE # SITE EASTING NORTHING SPECIES 1 PRV 663911 3799769 2 PRV 664869 3798163 KIRA(1), LEBI(1) 3 PRV 668480 3796545 SORA(1) 4 NP 652289 3766230 COMO(5), LEBI(1), PBGR(1), PUGA(2) 5 PRV 630499 3662049 SORA(2) 6 WMA 659928 3886264 7 WMA 663636 3881369 8 BKNWR 631521 3903308 AMBI(4), AMCO(3), PBGR(5), SORA(15), VIRA(1), W FIB(1) 9 BKNWR 629860 3899733 LEBI(1) 10 BKNWR 636273 3896796 11 BLNWR 759558 3971237 AMCO(1) 12 BLNWR 759456 3971431 13 BLNWR 760113 3972041 LEBI(1) 14 BLNWR 759732 3972159 KIRA(1), SORA(1) 15 BLNWR 759582 3971931 LEBI(1), SORA(1) 16 WMA 645810 3787981 17 WMA 631545 3787064 LEBI(1), PBGR(1), PUGA(1) 18 WMA 631860 3787639 19 WMA 631183 3787648 20 ACOE 651191 3766185 21 ACOE 651191 3766185 PBGR(1) 22 CRNWR 656445 3883412 23 CRNWR 651659 3881994 24 CRNWR 652133 3883089 25 CRNWR 655744 3870858 PBGR(6) 26 CRNWR 648592 3893807 27 CHIWRP 648535 3677639 MODU(15) 28 CHIWRP 649081 3676039 KIRA(1), MODU(3), SORA(3) 29 CHIWRP 648403 3677868 KIRA(3), MODU(2), SORA(2), VIRA(2) 30 CHIWRP 648472 3677087 KIRA(3), MODU(2), SORA(3) 31 WMA 638369 3702729 32 WMA 712245 4023050 33 WMA 712025 4023054 MODU(2) 34 WMA 711895 4023141 35 WMA 711878 4023434 36 WMA 711642 4023230 37 STFWRP 716579 3881323 MODU(5), PBGR(4) 38 STFWRP 712472 3881195 AMCO(1), KIRA(2), LEBI(1), SORA(1) 39 STFWRP 715022 3881275 AMCO(1), LEBI(2), PBGR(3) 40 STFWRP 717087 3880843 AMBI(1), AMCO(19), MODU(5), PBGR(4), SORA(1) 41 BLNWR 760236 3971963 AMBI(1), BCNH(1), LEBI(4) 42 PRV 633578 3668569 AMBI(1) 43 PRV 663568 3975806 44 PRV 663726 3976967 45 PRV 627788 3759213 46 WMA 762404 3976820 47 WMA 762063 3979516 48 WMA 702104 4016406 YCNH(3) 49 WMA 702164 4016136 YCNH(5) 50 PRV 601783 3787448 51 BLNWR 760106 3974234 COMO(1) 52 BLNWR 759370 3972004 53 BLNWR 759358 3975111 LEBI(1) 54 OFNWR 627039 3664398 KIRA(3), LEBI(1), MODU(2), VIRA(1) 55 OFNWR 626850 3662889 AMCO(2) 56 OFNWR 627163 3664947 LEBI(1) 57 OKNWR 652760 3745649 MODU(2), SORA(1) 58 OKNWR 652684 3744847 KIRA(3), SORA(1) 59 OKNWR 651978 3746153 SORA(1) 60 OKNWR 652450 3746429 BBWD(2), PBGR(2) 61 PLWRP 648066 3654962 SORA(1) 62 PLWRP 648279 3655295 SORA(2) 63 PLWRP 648285 3654144 LEBI(1), SORA(1) 64 PLWRP 648066 3654962 KIRA(2), SORA(1) 65 PLWRP 648075 3654859 66 PLWRP 647511 3653989 KIRA(1), LEBI(1) 67 PLWRP 647885 3654179 68 PRV 660763 3879480 LEBI(2) 69 PRV 601437 3791297 SORA(1), VIRA(1) 70 WAPANWR 753981 3913317 KIRA(1), SORA(1) 71 WAPANWR 752169 3917047 72 WAPANWR 751990 3917024 SORA(2), VIRA(1) 73 WAPANWR 751851 3917033 AMBI(1), PBGR(1), SORA(1) 74 WAPANWR 753062 3915822 Table 2. Birds located opportunistically listing date, species (refer to Appendix), count, and UTM coordinates. All birds listed were found while en route to other wetlands, or were audible or visible to the observer on wetlands located near the study sites.

DATE SPECIES COUNT EASTING NORTHING 4/14/05 BBW D 4 633578 3668569 4/14/05 COMO 2 664610 3731110 4/14/05 PBGR 6 664610 3731110 4/16/05 VIRA 1 627026 3664381 4/17/05 W HIB 4 627323 3663756 4/19/05 PBGR 4 647346 3653733 4/19/05 SORA 1 647470 3653891 4/19/05 SORA 1 648071 3654060 4/19/05 SORA 1 647920 3654088 4/19/05 SORA 1 648094 3653964 4/21/05 SORA 1 651348 3745275 4/22/05 AMCO 7 627163 3664947 4/22/05 BCNH 8 651283 3746300 4/26/05 AMCO 4 629907 3897273 4/26/05 AMCO 11 629913 3897713 4/28/05 AMCO 2 639504 3871730 5/3/05 AMCO 1 712415 3881197 5/3/05 AMCO 1 717091 3881197 5/3/05 AMCO 8 717181 3880939 5/3/05 BCNH 5 715024 3881276 5/5/05 SORA 1 754328 3914161 5/6/05 SORA 1 755288 3915206 5/6/05 PBGR 1 755676 3915090 5/28/05 YCNH 1 754357 3914129 5/29/05 YCNH 4 753970 3913297 6/13/05 COMO 2 643992 3701116 6/15/05 BBW D 9 636773 3685603 6/15/05 W HIB 1 636773 3685603 6/15/05 LEBI 2 636773 3685603 6/14/05 W HIB 15 627323 3663756 6/22/05 AMCO 1 625566 3797471 6/22/05 W HIB 14 625566 3797471 6/22/05 LEBI 2 625566 3797471 6/29/05 YCNH 1 751066 3917017

Acknowledgements

We would like to thank the Arkansas Game and Fish Commission for funding this project, their logistical support and assistance in every aspect needed. We would also like to thank Jonah Price for helping survey marshbirds. Karen Rowe (AGFC), Lake Lewis and Timmy Walker of Overflow NWR, Bill Alexander and Robert Pearrow of Bald Knob NWR, Aaron Mize of Big Lake NWR, Dennis Widner and Ryan Mollnow of Cache River NWR, Glen Miller of Wapanonca NWR, Brian Hollis and Willard Ryland of the NRCS, Richard Stock of Potlatch farms were all instrumental in logistical support. Thanks to John Bernhardt and Christopher W. Deren of the University of Arkansas Rice Research and Extension Center. Thanks to everyone at the Arkansas Cooperative Fish and Wildlife Research Unit.

Literature Cited

[AAS] Arkansas Audubon society. 2002. AAS bird records database, . Accessed 2005 Jul 25.

Brown, M., and J.J. Dinsmore. 1986. Implications of marsh size and isolation for marsh bird management. Journal of Wildlife Management 50(3):392-397

Conway, C. J. 2003. Standardized North American marsh bird monitoring protocols. Unpubl. USGS and Arizona Coop. Fish and Wildlife Research Unit, Tucson, AZ. 17pp.

Gibbs, J.P., and S.M. Melvin.1997. Power to detect trends in waterbird abundance with call-response surveys. Journal of Wildlife Management 61(4):1262-1267

King, S. L., and B. D. Keeland. 1999. Evaluation of reforestation in the lower Mississippi River alluvial valley. Restoration Ecology 7:348-359.

MacKenzie, D. I., J. D. Nichols, G. B. Lachman, S. Droege, J. A. Royle, and C. A. Langtimm. 2002. Estimating site occupancy rates when detection probabilities are less than one. Ecology 83:2248-2255.

Meanley, B. 1956. Food habits of the king rail in the Arkansas rice fields. Auk 73:252- 258.

Meanley, B. 1969. Natural history of the king rail. North American Fauna (67). Bureau of Sport Fisheries and Wildlife

Meanley, B. 1992. King rail. In The Birds of North America, No. 3 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC.: The American Ornithologists’ Union.

U.S. Fish and Wildlife Service. 2002. Birds of conservation concern 2002. Division of Migratory Bird Management, Arlington, Virginia.

Appendix. Four-letter codes for birds encountered

AMBI = American bittern VIRA = Virginia rail AMCO = American coot WHIB = white ibis BBWD = black-bellied whistling duck WFIB = white-faced ibis BCNH = black-crowned night heron LEBI = least bittern COMO = common moorhen MODU = mottled duck KIRA = king rail PBGR = pied-billed grebe YCNH = yellow-crowned night heron SORA = sora PUGA = purple gallinule