United States Department of Agriculture Natural Resources Conservation Service Conservation Practices Conservation Effects Assessment Project (CEAP) CEAP-Wildlife Conservation Insight Benefit Golden-winged December 2016 Warblers in Appalachia
cowbirds (Buehler et al. 2007 ). Of Summary of Findings • The post-fledging period, par- these factors, loss of quality breeding ticularly the first 4 days out of the habitat—young forests and shrublands The golden-winged warbler has nest, results in significant fledgling embedded in extensively forested experienced significant population mortality and could be a focal landscapes—is thought to be the most declines throughout its Appala- point for habitat management to significant (Roth et al. 2012). chian breeding range. Loss of increase reproductive output. breeding habitat is thought to be a The Golden-winged Wabler Working significant driver of these declines. • Quantifying differences in Group (gwwa.org) identified imple- post-fledgling survival among mentation of management prescrip- An assessment was conducted to management systems is critical tions that create or maintain gold- evaluate golden-winged warbler for comparing and evaluating each en-winged warbler breeding habitat response to habitat management system’s potential for successfully as a conservation priority (Roth et using conservation practices sug- contributing to golden-winged al. 2012). Recently, science-based gested by the Natural Resources warbler population recovery. guidelines for creating golden-winged Conservation Service’s (NRCS) warbler breeding habitat were devel- Working Lands For Wildlife oped (Bakermans et al. 2011, Roth et (WLFW) in the southern and • Ultimately, it is necessary that al. 2012). Conservationists are now central Appalachian states. Key both the nesting and post-fledging faced with the challenge of large-scale findings include: habitat needs of the golden-winged implementation of these habitat man- warbler are considered when agement guidelines to stabilize and developing conservation plans for reverse golden-winged warbler popu- • Most golden-winged warbler de- private landowners. mographics (e.g., territory density, lation declines. Habitat management adult survival, and nest surviv- targeting golden-winged warblers will al) did not differ among the five also likely benefit other at-risk birds management systems evaluated, that rely on young forest and shrub- thus indicating similar capabilities Background land including eastern whip-poor-will, to support breeding populations of prairie warbler, eastern towhee, field this species. The golden-winged warbler (Vermi- sparrow, and American woodcock vora chrysoptera) is a neotropical (North American Bird Conservation migrant songbird that winters in Initiative 2009, Roth et al. 2012). • Although some of the manage- portions of Central and South Amer- Additionally, many mature forest ment systems failed to achieve ica and breeds in the northern Great nesting songbirds and their offspring nest-site vegetation characteristics Lakes regions of the United States and use young forest and shrubland habitat in the ranges recommended by the Canada, and at higher elevations of during post-fledging and migration Golden-winged Warbler Conserva- the central and southern Appalachian (King et al. 2006, Vitz and Rodewald tion Plan (Roth et al. 2012), they Mountains (Confer et al. 2011). The 2006, Labbe and King 2014). still supported high nesting success. species is experiencing steep popu- lation declines throughout its Appa- While efforts to create and enhance • Juvenile and adult gold- lachian Mountains breeding range golden-winged warbler breeding hab- en-winged warblers used multiple (8.5% per year, Sauer et al. 2014) and itat on public lands in the Appalachian stages of forest succession (i.e., has thus become rare and patchily Mountains are underway, the fate of early, mid, and late successional distributed throughout this region. this species will likely depend on the forest) during the breeding and Several factors are thought to be driv- consistent availability of high quality post-breeding periods, thus stress- ing population declines of this song- habitat on private forestlands. In 2012, ing the need for managing local bird, including habitat loss in both the the USDA Natural Resources Conser- landscapes to create a mosaic of breeding and wintering range, hybrid- vation Service (NRCS) launched the forest age classes. ization with the blue-winged warbler, Working Lands for Wildlife (WLFW) and nest parasitism by brown-headed effort to create habitat on private lands for seven imperiled wildlife species warbler habitat uses domestic live- restrict the growth of woody vegetation including the golden-winged warbler. stock to limit natural succession. In and revert late successional shrublands Through cost-share assistance associat- areas where golden-winged warblers to earlier stages of succession having ed with WLFW, landowners are using are known to breed, low-intensity 30–60% shrub and sapling cover within conservation practices such as Early grazing (1 animal unit/2–4 ha) may the targeted area. A shrub and sapling Successional Habitat Development & be used during May-October or even cover closer to 60% allows immediate Management (NRCS Practice Code year-round if overgrazing is not nesting by golden-winged warblers, 647) to create early successional or occurring. High-intensity grazing (up while a cover closer to 30% may young forest patches within the forested to 1 animal unit/0.4 ha) may be used result in delayed nesting until woody landscapes of Appalachia that provide during non-nesting periods to limit vegetation recovers. critical nesting habitat for this imperiled natural succession in overgrown areas songbird. (i.e., those with >60% shrub cover). E. Prescribed Fire - Old Field: This management system maintains Due to significant landscape heteroge- C. Prescribed Fire - Young Forest: existing shrubland habitat as old fields, neity across the Appalachian Mountains This management system creates new including abandoned agricultural areas portion of the golden-winged warbler’s and maintains existing golden-winged and reclaimed surface mines, primarily range, there are numerous ways in warbler nesting habitat using pre- through the use of prescribed burning. which young forest nesting habitat scribed fire as preparatory treatment The result of this management system can be created or maintained for the for a timber harvest or as a method of is an early successional shrubland species. These treatments can be cate- maintaining early successional habitat with herbaceous cover and slowed gorized into five primary management after a harvest. Maintaining the area in growth of woody plants such as systems (Fig. 1). early succession with prescribed fire shrubs and saplings. Prescribed fire on may mimic natural disturbance events Appalachian surface mines can be used A. Timber Harvest: This management that historically created breeding habi- to set back vegetative growth, but it system creates new golden-winged war- tat for golden-winged warblers. must be used regularly to maintain the bler nesting habitat via stands of young, area in an early successional state. regenerating forest with adequate D. Old Field Management: This residual trees. Timber Harvest involves management system can be used Assessment Partnership removing overstory and results in a to maintain golden-winged warbler regenerating forest with abundant sap- habitat through the use of the Monitoring the response of golden- lings, shrubs, and forbs. Live residual NRCS conservation practice Brush winged warblers to habitat established trees are usually the largest and health- Management and associated practices. via NRCS conservation practices is iest of the deciduous hardwoods in the This management practice sets back necessary in order to 1) evaluate the stand, and snags are also retained. the succession of shrubs and other effectiveness of primary management woody plants primarily by using systems, 2) quantify WLFW’s relative B. Grazing Management: This method mechanical methods to remove some contribution to the species’ recovery, of maintaining existing golden-winged woody vegetation. The goal is to and 3) provide data necessary to
Figure 1. Five primary management systems used to provide early successional breeding habitat for golden-winged warblers: (A) timber harvest, (B) grazing management, (C) prescribed fire - young forest, (D) old field management, (E) prescribed fire - old field. 2 modify existing practice guidelines via adaptive management to improve WLFW program effectiveness.
In 2012, NRCS formed a Conservation Effects Assessment Project (CEAP) partnership with the Indiana Universi- ty of Pennsylvania Research Institute to lead a team of scientists represent- ing several universities, state and fed- eral agencies, and non-governmental conservation organizations to assess golden-winged warbler response to NRCS WLFW activities. The assess- ment used multiple sites in four Appa- lachian states to represent the scope of habitats and WLFW practices across the species’ Appalachian Mountains breeding range. The study approach and findings of the first three years of this assessment are presented in detail by Aldinger et al. (2015). Highlights of the assessment are presented in this Conservation Insight. Additional work is underway to fine-tune initial findings and to assess benefits to other birds associated with early succession- al habitats.
Assessment Approach
The assessment focused on evaluating the demographic response of gold- en-winged warblers to habitat manage- ment guided by NRCS conservation practices at 70 sites located across portions of the species’ Appalachian Mountains breeding range (Fig. 2). For each of the five management systems, assessments were made for (1) gold- en-winged warbler minimum annual Figure 2. Assessment study sites were located throughout the Appalachian Mountains survival, territory size, and density and within the golden-winged warbler breeding range. derived from territory mapping; (2) territory density derived from point ping. The number of sites studied for counts; (3) nest survival and fledgling each management system were: timber productivity; (4) attainment of recom- harvest (n=26), grazing management mended nesting vegetation; (5) space (n=12), old field management (n=17), use by radio-tagged adult males; (6) prescribed fire - old field (n=2), and fledgling survival, movements, and prescribed fire - young forest (n=13). habitat use; and (7) implications drawn Captured males were fitted with a stan- from these analyses on golden-winged dard USGS aluminum leg band and a warbler demographic response to unique combination of 1–3 additional USDA conservation practices. color leg bands (Fig. 3). Minimum annual survival was estimated us- Annual survival, territory size, and ing re-sighting data and the program territory density MARK (version 7.1, Colorado State Male golden-winged warblers were University, Ft. Collins, Colorado, captured with mist nets and banded USA). Field technicians visited each Figure 3. A male golden-winged warbler annually to estimate minimum survival study site every 1–3 days to visually fitted with an aluminum USGS leg band rates and to aid in the identification of locate marked territorial males and and a unique combination of plastic color individual males during territory map- record associated geographic coor- bands for identification purposes.
3 dinates. Approximately 30 locations of each plot’s center, the species and “attainment” was associated with the per individual male were recorded on dbh of all trees (>10 cm dbh), number proportion of stand-level plots having at least eight separate days during the of snags (>10 cm dbh), average shrub vegetation characteristics that fell breeding season. Locations for each height, and average sapling height within ranges recommended by Roth male (within a single breeding season) were also recorded. et al. (2012). Recommended values for were used to delineate territory bound- vegetation within 1-m of nest sites in- aries. Territory size was estimated for Nest survival: All golden-winged clude 0-10% bare ground, 5-25% grass each male during each breeding season warbler nests that reached at least the cover, 4-45% forb cover in herba- from 2012–2014. Estimates of territory egg-laying stage (i.e., active nests) ceous-dominated sites (grazing man- density (males/ha) for each study site were included in nest-survival anal- agement, old field management, and and for each management system as a yses. Two groups of models were prescribed fire - old field), 45-100% whole were also made to enable com- developed for golden-winged warbler forb cover in silviculturally-derived parisons among management systems. nest daily survival rate (DSR). Model sites (prescribed fire - young forest suite I featured management system, and timber harvest), 5-40% Rubus Golden-winged warbler territory study area, time within season, veg- cover, and 5-50% woody cover. density was also estimated using data etation community type, and year collected during 10-minute point covariates. Model suite 2 included Space use by adult male golden- count surveys (n=95 sites). Each point models with vegetation covariates winged warblers count survey location was visited 1–3 within each management system. Nest Between May and June 2012 and times annually during the peak of the survival for each management system 2013, adult male golden-winged breeding season (May 10–June 25). was analyzed separately. Prescribed warblers were captured at 16 sites Over a 10-minute period, a laser range fire - young forest was excluded due to in Pennsylvania and West Virginia. finder was used to record the exact small sample size. Study sites were categorized as old distance from the point count location field management (n=7), prescribed to all golden-winged warblers detect- Fledgling productivity: Golden- fire - young forest (n=3), and grazing ed. To characterize habitat conditions, winged warbler fledgling productivity management (n=6). Nineteen (n=19) a detailed vegetation survey was also (number of fledglings produced/ha) males that weighed ≥9 g were each collected at each point count location. was estimated for each management equipped with radio transmitters and Two model suites exploring warbler system. Fledgling productivity was fitted with a metal U.S. Geological density were evaluated: model suite 1 the product of four components: 1) Survey leg band and a unique combi- (elevation, latitude, and management probability of nest success given nation of color bands for visual iden- system effects) and model suite 2 three nesting attempts, 2) number of tification purposes. Visually mapped (vegetation effects). fledglings produced per successful territories and telemetry-based home nest, 3) territory density, and 4) male ranges for each male were delineat- Nest survival and fledgling pairing rate. Territory density for ed using 100% and 50% minimum productivity each management system was the convex polygons (MCPs) in ArcMap. During 2012–2014, nests of golden- mean of the across-year territory The amount of overlap between each winged warblers were located and mapped densities for sites within radio-tagged male’s visually mapped monitored on 46 sites. Sites were each management system. A constant territory and telemetry-based home searched multiple times weekly to locate pairing rate (0.8) was used among range was measured using the intersect nests using behavioral cues of adults. management systems based on a tool in ArcMap. Vegetation data were Once a nest was found, it was monitored compilation of pairing rates from collected within each visually mapped to determine nest fate. A nest was golden-winged warbler populations territory and at all telemetry locations classified as “successful” if at least one across the Appalachian Mountains that were ≥12 m outside the visually golden-winged warbler nestling fledged. region (Confer et al., unpubl. data). mapped territory (to prevent potential overlap of sampling areas). Vegetation characteristics were mea- Attainment of recommended nesting sured at nests after nest fate was deter- vegetation Fledgling survival, movements, and mined. A nested plot design (1-m, 5-m, The same vegetation protocol used habitat use and 11.3-m radius) was used to survey to survey nest sites was also used at Study sites in Pennsylvania (timber vegetation centered at nest sites. Per- plots distributed randomly (1 plot/ harvest sites, n=8) and Tennessee (pre- cent cover for leaf litter, bare ground, ha) throughout each study site (here- scribed fire - old field sites, n=2) were grasses, forbs, vines, blackberry/rasp- after, “stand-level plots”). Stand-level searched multiple times weekly to berry (Rubus spp.), and woody plant plots quantified the vegetation char- locate nests during 2013–2014. When species within a 1-m radius of plot acteristics available across each site. nestlings were 7–8 days old (1–2 days centers were recorded. Within 5 m of One primary management target for prior to the anticipated fledge date), plot centers, 1–2 m tall shrubs (“short golden-winged warbler nesting habitat 1–3 birds were briefly removed from shrubs”), >2 m tall shrubs (“tall was the nesting vegetation recom- their nest and weighed, and then a leg shrubs”), and saplings (1–10 cm diam- mended in the Golden-winged Warbler band was attached. A radio transmitter eter at breast height—dbh, >0.5 m tall) Conservation Plan (Roth et al. 2012). was also attached to each bird using were tallied by species. Within 11.3 m Recommended nesting vegetation a figure-eight harness. The combined
4 mass of radio transmitter, harness, and management system effects) included achieve average sapling densities that leg band was < 5% of each nestling’s linear elevation and latitude effects range between 3,000–8,400 stems/ha weight. Radio-tagged individuals that and an interaction between these two (1,300–3,300 stems/acre). successfully fledged were tracked variables. At southern latitudes den- daily to record each fledgling’s exact sity increased with elevation, and at Nest survival: Across 46 sites, the location and survival status. Two northern latitudes density decreased survival of 288 golden-winged groups (TN and PA) were used to with elevation. Models with manage- warbler nests was monitored during model fledgling survival, and days 1–4 ment system had essentially no support 2012–2014. Of these nests, 79, 86, 61, and days 5–25 were analyzed sepa- (ΔAIC > 10, Burnham and Anderson 48, and 14 nests were found in timber rately because survival was noticeably 2002), suggesting that golden-winged harvest, old field management, grazing lower in the first 4 days. warbler density overall was consistent management, prescribed fire - old among management systems. The field, and prescribed fire - young forest Assessment Findings best-supported density model in model sites, respectively. Overall DSR for all suite II (vegetation covariates) in- golden-winged warbler nests was 0.963 Minimum annual survival: Over 3 cluded a sapling count effect whereby ± 0.003, which equates to a probability field seasons, 290 male golden-winged density increased with sapling count. of 0.767 ± 0.035 of producing a warblers were captured and banded This finding is consistent with previ- successful nest, given three attempts. across all five management systems: ous management recommendations to Successful golden-winged warbler timber harvest, n=88; old field man- agement, n=107; prescribed fire - young forest, n=13; prescribed fire - old field n=22; and prescribed grazing, n=60. Adult male annual survival by management system ranged wide- ly from 0.40 to 0.81 (Fig. 4). When combining birds from all management systems, the average survival rate was 0.58, which falls near the rate (0.62) found in Bulluck et al. (2013) in Ten- nessee and Ontario.
Territory size: Over 3 field seasons, 526 golden-winged warbler territories were mapped within 70 study sites. Of these, 474 territories met the criteria for inclusion in territory size comparisons among the 5 management systems. Average territory size Figure 4. Minimum annual survival rate estimates (± SE) for adult male golden-winged was largest for those in grazing warblers. management sites (1.77 ha, n = 98) and smallest for timber harvest (0.82 ha, n = 172) (Fig. 5).
Territory density derived from territory mapping: Golden-winged warbler territory densities across the 70 sites that were territory mapped ranged from 0.0–4.61 males/10 ha. Mean golden- winged warbler density estimates by management system ranged from 1.05–3.37 males/10 ha with a mean density of 1.5 males/10 ha across all five management systems (Table 1).
Territory density derived from point counts: A total of 864 point count surveys were completed at 191 unique locations across 70 sites during Figure 5. Territory sizes of golden-winged warblers mapped in 2012-2014. Error bars 2012–2014. The best-supported gold- represent 95% confidence intervals. Sample sizes were: grazing magagement (GRAZ) en-winged warbler density model in = 86, old field mangagement (OLFD) = 159, prescribed fire - old field (PF-OF) = 45, model suite I (elevation, latitude, and prescribed fire - young forest (PF-YF) = 22, and timber harvest (TIMB) = 162.
5 nests (n = 143) produced on average at 2,719 random plots across 45 nest vegetation variables occurred 4.0 ± 0.1 fledglings. For model suite I managed sites over the course of our in 39 of 2,719 (1.4%) random plots. (management system, study area, time study (746 in grazing management, The average number of variables within season, vegetation community 627 in old field management, 146 that attained recommended levels type, and year covariates), DSR in prescribed fire - old field, 335 in simultaneously within a single decreased as the season progressed prescribed fire - young forest, and 865 random plot ranged from 1.9 (SE: (Fig. 6). For models that included in timber harvest). The attainment 0.12) in timber harvests to 2.5 (SE: management system, DSR was of recommended levels for all five 0.08) in grazing management sites. similar among management systems. However, the probability of producing Table 1. Mean territory density (males/10 ha) across each of five management systems. a successful nest given three attempts (a common number of attempts among Number of Golden-winged warbler study areas according to Aldinger et Management system sites territory mean (±SE) density al. 2015) showed more differentiation mapped among management systems and was Grazing management 12 1.26 (0.30) lowest for prescribed fire - young forest (Fig. 7). Old field management 17 1.39 (0.31) Prescribed fire - old field 2 3.37 (0.82) The effects of vegetation (model Prescribed fire - young forest 13 1.05 (0.41) suite II) on nest success was evaluat- ed within each management system. Timber harvest 26 1.69 (0.30) Prescribed fire - young forest was not analyzed due to small sample size (n=13 nests). Modelling revealed that, for timber harvest and prescribed fire - old field, nest survival was not well explained by vegetation vari- ables. It is inferred from these results that timber harvest and prescribed fire - old field consistently produced vegetation characteristics associated with average nesting success. There were significant effects of vegeta- tion variables on nesting survival for grazing management and old field management. Intermediate levels of Rubus were best for nest survival on grazing management sites, whereas tall shrub (>2m) count was negatively associated with nest survival on Old Figure 6. Daily survival rate (DSR) of golden-winged warbler nests decreased as the 69- Field Management sites (Fig. 8). day nesting season progressed. Fledgling Productivity: Mean gold- en-winged warbler fledgling pro- ductivity across all five management systems was 0.56 (± 0.10) fledglings/ ha. Fledgling productivity among the management systems ranged from 0.21 ± 0.16 fledglings/ha for pre- scribed fire - young forest sites to 0.87 ± 0.23 fledglings/ha for prescribed fire - old field sites (Fig. 9). However, these two management systems also had the widest variation in two of the productivity components: 1) probabili- ty of nest success given three attempts and 2) number of young fledged per successful nest. Figure 7. Probability of golden-winged warbler nest success (± SE) given three attempts among management systems: grazing management (GRAZ), old field mangagement Attainment of recommended nesting (OLFD), prescribed fire - old field (PF-OF), prescribed fire - young forest (PF-YF), and vegetation: Vegetation was quantified timber harvest (TIMB).
6 Golden-winged warbler territories Pennsylvania and 488 telemetry and dance was greater in home ranges (7.3 are structurally diverse and must 616 visually mapped locations among trees/11.3-m radius plot ± 0.8) than in support activities other than nesting 7 males in West Virginia were record- visually mapped territories (1.9 ± 0.6) (e.g., singing, foraging, and fledgling- ed. Telemetry-delineated home ranges and telemetry locations were closer rearing). Thus, while it is important were 2–4 times larger than visually (14.3 m ± 8.0) to intact forested edges that managed sites provide multiple mapped territories (Table 2, Fig. 10) than were visually mapped locations options for nest placement, the (Frantz et al. 2016). (44.8 m ± 6.7). More telemetry loca- attainment of recommended levels tions than visually mapped locations of nest site vegetation should not be Forty percent of radio telemetry loca- occurred in forest in both states. On expected to approach 100% across an tions were outside of visually mapped several occasions, radio-marked entire site. territories. Sapling abundance was individuals were observed >200 m greater in home ranges (mean 20.7 (maximum of 1.5 km) from their Space use of radio-tagged adult saplings/5-m radius plot ± 2.9 SE) than visually mapped territory boundaries. males: A total of 524 telemetry and in visually mapped territories (11.5 Why golden-winged warblers left their 439 visually mapped locations among ± 2.9) in Pennsylvania. In managed visually mapped territories is unknown, 12 male golden-winged warblers in pastures of West Virginia, tree abun- but observations suggest foraging, ex- tra-pair copulation, and reconnaissance for post-breeding movement as possi- ble motives (Frantz et al. 2016).
Fledgling survival: A total of 76 fledglings were radio-tracked during the 2-year post-fledging study (TN 2013, n = 10; TN 2014, n = 31; and PA 2014, n = 35). Depredation was greatest during the first four days after fledging, with 81% (34/42) of the mortalities occurring within this period. Daily survival increased considerably thereafter (5+ days post-fledging). Daily survival for the Figure 8. Vegetation features associated with nest survival as described by best-support- ed models of golden-winged warbler nest survival. Grazing management showed nest 5–25 day interval was 98.7 ± 0.8% in survival related to percent Rubus cover within 1 m in a manner where intermediate levels Tennessee and 98.2 ± 0.8% in Penn- were best. The model for Old field Management revealed that tall shrub (>2m) count sylvania. Fledgling survival for the within 5 m of the nest was negatively associated with nest survival. entire 25-day post-fledging period was 25.3 ± 8.2% in Tennessee and 45.5 ± 13.3% in Pennsylvania. Average shrub height at each fledgling loca- tion was the most important habitat feature associated with daily survival, as fledgling survival was negatively related to average shrub height during the first four days after fledging.
Fledgling habitat use and movement: Habitat use changed considerably as the fledglings aged over their first 30 days post- fledging. Very young fledglings (<5 days out of the nest) used primarily early-successional habitat on the first day post-fledging but gradually used other cover types as they aged (Figs. 11 and 12). By Day-12 post-fledging, early- successional habitat made up less Figure 9. Fledgling productivity among management systems. Fledgling productivity than half of total cover types used was the product of four components: (1) probability of nest success given three nesting by fledglings in Pennsylvania and attempts, (2) number of fledglings produced per successful nest, (3) territory density, and Tennessee. Fledglings studied in (4) pairing rates. Low and high estimates were calculated using lower and upper 95% Tennessee used proportionally more confidence intervals. pole-staged stands than fledglings in
7 Table 2. Size comparisons of radio-marked golden-winged warbler visually mapped territories and telemetry-delineated home ranges using 50% and 100% minimum convex polygons (MCPs). Visually mapped territory (ha) Telemetry-delineated home range (ha)
Metric State n Mean ± SE Range Mean ± SE Range Territory Size (ha): 100% MCP PA 12 1.7 0.2 0.65–3.69 6.3 1.7 1.40–19.76 WV 7 2.4 0.5 0.79–4.77 11.8 6.2 2.27–47.99 50% MCP PA 12 0.3 0.1 0.12–0.69 0.5 0.1 0.13–1.03 WV 7 0.3 0.1 0.13–0.63 0.6 0.1 0.20–1.28
Figure 10. A visually mapped territory (gray) and telemetry-delineated home range (dashed polygon) for an individual male golden-winged warbler in West Virginia. This individual’s visually mapped territory over- lapped with one other individual’s visually mapped territory (hollow polygons), but his telemetry-delineated home range over- lapped with portions of visually mapped ter- ritories of nine other males. Visually mapped territory point locations are represented as circles and telemetry locations as stars.
8 Figure 11. The use of five different cover types by golden-winged warbler fledglings during four time intervals across the first 30 days post-fledging. (Note: Wetlands and shelterwoods were not present in the Tennessee study area.)
Figure 12. An example of mid-succession- al habitat used by older golden-winged warbler fledglings in Pennsylvania—often a patch of moderately dense regeneration within canopy gaps created by individual Figure 13. Daily movement patterns of fledgling golden-winged warblers inTennessee tree falls or gypsy moth mortality. and Pennsylvania over the first 20 days post-fledging. Movement is measured as day-to- day movements and distance to nest.
Pennsylvania over all time intervals. Putting Findings into Practice drastically. To reverse these population Pennsylvania birds used wetlands declines, many government natural and shelterwoods (which were The purpose of this assessment was resource agencies and their partners are not available in Tennessee) more to evaluate golden-winged warbler using active management (e.g., timber frequently as they aged. Day-to- response to active habitat management harvest, brush mowing, and prescribed day movements and total distance using conservation practices suggested fire) to increase the availability of early from the nest increased during by NRCS’s Working Lands for Wildlife successional communities in forested each of five time steps examined in the southern and central Appalachian landscapes. The financial and human for all radio-marked individuals states. Golden-winged warbler popula- resource costs associated with these (Fig. 13). Figure 14 shows the daily tions, and those of many other wildlife efforts are often considerably high. As movements of a fledgling golden- species that require forested landscapes such, evaluating which conservation winged warbler in Pennsylvania. with a mix of young and old succes- systems are effective and identifying sional communities, have declined potential ways to improve management
9 • Golden-winged warbler density increased linearly with sapling count. Management should result in average sapling densities that range between 3,000–8,400 stems/ha (1,200–3,300 stems/acre). • Although the simultaneous attainment of recommended levels of the five nest site vegetation characteristics presented in the Golden-winged Warbler Conservation Plan (Roth et al. 2012) was rare for all five management systems, they still maintained the capacity to produce high-quality nesting habitat. • While WLFW sites were used by golden-winged warblers, there are a few aspects of vegetation that managers need to pay close attention to in order to improve attainment of recommended levels outlined in the Golden-winged Warbler Conservation Plan. Specifically, woody-dominated sites (timber harvest and prescribed fire - young forest) generally needed more grass cover (observed 2–6% vs. the recommended 5–25%) and herbaceous-dominated sites (old field management, grazing, and prescribed fire) needed to reduce grass cover (observed 30–35% vs. the recommended 5–25%). The recommended values for these particular vegetation components can be achieved by incorporating the appropriate facilitating practices into Figure 14. An example of a 27-day movement pathway of a fledgling golden-winged NRCS conservation plans. warbler within a timber harvest management system site in Pennsylvania. • This assessment represents one of the single largest efforts to relate effectiveness is important. Assessment • Golden-winged warbler territories golden-winged warbler nesting findings can be used to maximize the were relatively small with most success to a suite of specific land contribution of NRCS’s Working Lands (>90%, n = 463) defended territories management systems. Two hundred for Wildlife to reversing the decline of being <3 ha (7.5 acres) in size. eighty-eight golden-winged warbler this imperiled songbird. Average territory size was greatest nests across all study areas were found for grazing sites (1.77 ha) and least and monitored. Management system • Many of the golden-winged warbler for timber harvests (0.82 ha). Across itself was not associated with survival demographic metrics assessed (e.g., all sites, regardless of management of golden-winged warbler nests. annual adult survival, territory density, system, territory size averaged 1.36 ha and nest survival) did not differ among (3.5 acres). • Individual management systems the five management systems (timber supported different vegetation harvest, prescribed fire - young forest, • On average, managed sites supported relationships with respect to nest prescribed fire - old field, grazing 1.5 males/10 ha (0.6 males/10 acres). survival. Timber harvest and management, and old field man- prescribed fire - old field had no agement), thus indicating that each • Across all management systems, apparent relationships with micro- was effective at supporting breeding adult males had a minimum annual habitat characteristics while old populations of this species in the land- survival probability of 0.58 (± 0.04, n field management and grazing scapes where it was applied. = 290 males). management nests survived as a 10 function of >2-m tall shrubs and Resources Conservation Service Frantz, M.W., K.R. Aldinger, P.B. Rubus, respectively. practices. A Conservation Effects Wood, J. Duchamp, T. Nuttle, A. Assessment Project (CEAP), USDA- Vitz, and J.L. Larkin. Space and • Average fledgling productivity Natural Resources Conservation habitat use of breeding golden- across management systems was 0.56 Service, Washington, D.C. winged warblers in the central fledglings/ha (1.38 fledglings/acre). Appalachian Mountains. In H.M. Aldinger, K.R., T.M. Terhune II, P.B. Streby, D. Buehler, and D.E. • Radio telemetry revealed that adult Wood, D.A. Buehler, M.H. Baker- Andersen (editors), golden-winged males often (in 40% of locations) mans, J.L. Confer, D.J. Flaspohler, warbler ecology, conservation, and move beyond their defended J.L. Larkin, J.P. Loegering, K.L. habitat management, pp. 81-94, territories. These frequent, and Percy, A.M. Roth, and C.G. Smalling. Studies in Avian Biology (no. 49), sometimes long-distance (1 km), 2015. Variables associated with nest CRC Press, Boca Raton, FL. movements into areas with different survival of golden-winged warblers vegetation structure than found in (Vermivora chrysoptera) among King D.I., R.M. Degraaf, M.L. Smith, typical nesting habitat indicates the vegetation communities commonly J.P. Buonaccorsi. 2006. Habitat importance of managing for a diversity used for nesting. Avian Conservation selection and habitat specific surviv- of forest age classes at the local and Ecology 10 (1):6. [online] URL: al of fledgling ovenbirds(Seiurus landscape scale. http://www.ace-eco.org/vol10/iss1/ aurocapilla). Journal of Zoology art6/ 269:414–421. • The concept of providing young forest nesting habitat within a mosaic Bakermans, M.H., J.L. Larkin, B.W. Labbe M.A., and D.I. King. 2014. The of other forest age classes is also Smith, T.M. Fearer, and B.C. Jones. effect of local and landscape-level 2011. Golden-winged warbler important for the post-fledging period. characteristics on the abundance of habitat best management practices The 76 fledglings monitored used a forest birds in early-successional hab- in forestlands in Maryland and itats during the post-fledging season combination of early-, mid-, and late- Pennsylvania. American Bird in western Massachusetts. PLoS ONE successional communities within the Conservancy. The Plains, Virginia. 9(8): e106398. doi:10.1371/journal. first 25 days post-fledging. 26 pp. pone.0106398
• Fledgling survival was examined Buehler, D.A., A.M. Roth, R. Vallen- North American Bird Conservation in two management systems (old der, T.C. Will, J.L. Confer, R.A. Initiative. 2009. http://www.nabci-us. field-prescribed fire and timber har- Canterbury, S.B. Swarthout, K.V. org (17 December 2015). vest) and was found to be significantly Rosenberg, and L.P. Bullock. 2007. higher in timber harvest. Status and conservation priorities of Roth, A.M., R.W. Rohrbaugh, T. Will, golden-winged warbler (Vermivora and D.A. Buehler (editors). [online]. • Reduced shrub height (<0.5m) may chrysoptera) in North America. Auk 2012. Golden-winged warbler status increase juvenile survival during the 124:1439-1445. review and conservation plan.
Confer, J.L., P. Hartman, and A. Roth. White, G.C., and K.P. Burnham. 1999. References 2011. Golden-winged warbler Program MARK: Survival estimation (Vermivora chrysoptera). In A. Poole, from populations of marked animals. Aldinger, K.M. Bakermans, D.J. editor, The Birds of North America, Bird Study 46:120–139. McNeil, J. Lehman, A. Tisdale, and Number 20. Academy of Natural J.L. Larkin. 2015. Final Report: Sciences, Philadelphia, and American Monitoring and evaluating golden- Ornithologists’ Union, Washington, winged warbler use of breeding D.C. habitat created by the Natural 11 Conservation Effects Assessment Project: Translating Science into Practice The Conservation Effects Assessment Project (CEAP) is a multiagen- cy effort to build the science base for conservation. Project findings will help to guide USDA conservation policy and program devel- opment and help farmers and ranchers make informed conservation choices. One of CEAP’s objectives is to quantify the environmental benefits of conservation practices for reporting at the national and regional levels. Because wildlife is affected by conservation actions taken on a variety of landscapes, the CEAP-Wildlife National Component complements the CEAP national assessments for cropland, wetlands, and grazing lands. The Wildlife National Assessment works through numerous partnerships to support relevant assessments and focuses on regional scientific priorities. This assessment was conducted through a partnership among NRCS, Indiana University of Pennsylvania (IUP), American Bird Conser- vancy, West Virginia University, USGS West Virginia Cooperative Research Unit, North Carolina Audubon, Worcester Polytechnic Insti- tute, University of Tennessee, and Appalachian State University. The primary investigator on this project was Jeff Larkin (IUP). For more information: www.nrcs.usda.gov/technical/NRI/ceap/, or contact Charlie Rewa at [email protected].
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