Survival and habitat use by post-fledging forest-nesting songbirds in managed mixed northern hardwood-coniferous forests.

University of Minnesota Ph.D. dissertation. November 2010. Major: Natural Resources Science and Management. Advisor: Dr. David E. andersen. 1 computer file (PDF); xi, 148 pages.Until recently, studies of breeding migratory songbirds have been primarily limited to the nesting season. Therefore, there is very little information about songbird survival and habitat use during the post-fledging period (i.e. the time between nesting and fall migration) available to those making management decisions. I expanded on the traditional nest-monitoring study and used radio telemetry to monitor survival and habitat use of fledgling songbirds in managed northern hardwood-coniferous forests of northern-Minnesota. In addition, I used mist-nets to sample use of early-successional forest stands (regenerating clearcuts) and forested wetlands by mature forest-nesting birds during the post-fledging period. I found that many assumptions of songbird nesting studies are unreliable, including the common assumption that the presence of a family group is confirmation of a successful nest in an occupied territory. In addition, I found that annual fledgling survival can vary considerably, and does not vary consistently with nest productivity, a finding with broad implications for models of songbird population growth. Furthermore, I found that habitat used by birds during the post-fledging period can be considerably different than that used for nesting, and that post-fledging habitat use can affect fledgling survival. In addition, I found that factors commonly affecting nest productivity (e.g. edge effects) can affect fledgling survival differently. From mist-netting, I found that many mature-forest birds used non-nesting cover types during the post-fledgling period, but most of that use was by only a few species, and hatch-year birds rarely used non-nesting cover types before independence from adult care. Models of capture rates in non-nesting cover types indicated that use of non-nesting cover types by mature-forest birds was primarily related to food availability and secondarily to cover in the form of relatively dense vegetation. My results indicated that nearly every conclusion made about breeding population ecology of mature-forest birds based only on nesting data was contradicted by data from the post-fledging period. My results clearly demonstrate that data from the entire breeding season (nesting and post-fledging) are necessary to understand songbird seasonal productivity and habitat associations.Streby, Henry M.. (2010). Survival and habitat use by post-fledging forest-nesting songbirds in managed mixed northern hardwood-coniferous forests.. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/101017

DEMOGRAPHIC RESPONSE OF GOLDEN-WINGED WARBLER TO HABITAT MANAGEMNET ACROSS A CLIMATE CHANGE GRADIENT IN THE CORE OF THE SPECIES' RANGE: 2012 SUMMARY REPORT

In 2012 we repeated our 2011 efforts with a substantial increase in data collected. This was the second and final full field season investigating population ecology of Golden-winged Warblers (Vermivora chrysoptera; hereafter GWWA) at Tamarac National Wildlife Refuge (NWR) and Rice Lake NWR in Minnesota and Sandilands Provincial Forest (PF) in Manitoba. We assessed nesting habitat use, nest productivity, fledgling survival, and post-fledging habitat use by GWWA at all three sites. We color banded 107 adult female and 112 adult male GWWA and we attached radio transmitters to 108 adult females. By tracking radio-marked females and by nest searching, we found and monitored 149 nesting attempts including 2 nests found by others conducting research at Tamarac NWR (see acknowledgments). The 66% increase over the 2011 nest sample was partly due to increased effort to radio-mark adult females, but mostly to the return of many experienced nest searchers from 2010 and 2011. We banded 311 nestlings and fledglings and radio-tracked 175 fledglings. We collected data on habitat characteristics and GWWA behavior at >2,400 adult, nest, and fledgling locations. Including renesting, we estimated that 58%, 74%, and 79% of females successfully nested and that 53%, 49%, and 48% of fledglings survived to independence from adult care at Tamarac NWR, Rice Lake NWR, and Sandilands PF, respectively. Interestingly, the increases (over 2011) in successfully nesting females at Rice Lake NWR and Sandilands PF were accompanied by considerable decreases in fledged brood size due to many partial-brood nest predation events, and the decrease in successfully nesting females at Tamarac NWR was accompanied by a considerable increase in fledged brood size. Similar to 2011, nest failure and fledgling mortality were due nearly entirely to predation at the Minnesota sites, whereas weather exposure and blowfly infection accounted for a relatively high percentage (23%) of fledgling mortalities at Sandilands PF. Unlike previous years, we tracked at least one (total = 6) nestling or young fledgling at each site to a garter snake (i.e., inside the snake), possibly reflective of the warmer, dryer early spring weather. Consistent with 2011, 30% of radio-marked females nested in older forest stands traditionally not considered GWWA habitat, and fledged family groups moved into and spent much of the post-fledging period in those older forest areas. Early findings from this project have been disseminated in 2 peer reviewed scientific journal articles and 2 more are currently in review. Detailed analyses for manuscripts about transmitter effects, population dynamics, micro- and macro-scale habitat associations, nest-site choice, parental care of fledglings, and interesting natural history observations are all underway.Streby, Henry M; Peterson, Sean M; Andersen, David E. (2012). DEMOGRAPHIC RESPONSE OF GOLDEN-WINGED WARBLER TO HABITAT MANAGEMNET ACROSS A CLIMATE CHANGE GRADIENT IN THE CORE OF THE SPECIES' RANGE: 2012 SUMMARY REPORT. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/183612

Post-fledging survival, movements, and habitat associations of Gray Vireos in New Mexico

Annual population growth in songbirds can be particularly sensitive to post-fledging survival, but research and management are frequently biased toward the nesting stage. Post-fledging information is particularly scarce for species breeding in desert bird communities, many of which have collapsed in recent decades. During 2017–2019 at Sevilleta National Wildlife Refuge, New Mexico, USA, we used radio telemetry to monitor survival, movements, and habitat associations of 90 fledgling Gray Vireos (Vireo vicinior), a desert-dwelling species of conservation concern. We used logistic exposure models to investigate the relationship between fledgling survival and habitat features at two spatial scales. Overall, we estimated that 51 ± 8% of fledglings survived the monitoring period. All mortalities occurred during the first 12 days post-fledging and were attributed to predation and environmental exposure. In daily survival models focused on predation mortalities, age was the strongest predictor of survival. Daily survival rate was not related to any habitat variables we measured. Percent tree cover used by birds during the first 12 days post-fledging was similar to that of nesting sites and greater than that of random locations. Similarly, fledglings occupied individual trees and shrubs with lateral vegetation cover similar to that of nest locations. Minimum daily distance traveled, distance from nests, and variance associated with these measures, all increased with age. Except for the use of a larger area, habitats used by Gray Vireos during the post-fledging period were similar to those used for nesting in our study population, indicating that maintenance of large patches of moderately dense juniper is desirable for this species. More study is needed from populations in less pristine and more heterogeneous landscapes. More broadly, given the importance of first-year survival in demographic models and the declines of dryland birds, information is needed on the post-fledging period of many desert songbirds

Life history characteristics of birds influence patterns of tick parasitism

Introduction: Birds serve as reservoirs for tick-borne pathogens as well as hosts for multiple tick species of public health relevance.  Birds may perpetuate life cycles of vectors and vector-borne pathogens and disperse disease vectors over long distances, supplementing populations at range margins or seeding invading populations beyond the edges of current tick distributions.  Our goal for this study was to identify life history characteristics of birds that most strongly affect tick parasitism. Materials and Methods: We collected 6203 ticks from 5426 birds from two sites in eastern North America and used field-derived parasitism data and published literature to analyze impacts of life history factors on tick parasitism in birds. Results and Discussion: We identified body size and nest site to have the strongest impact on tick prevalence and abundance in the songbird species included in this study.  Our findings reveal site-independent patterns in tick parasitism on birds and suggest that physical more than behavioral characteristics may influence a bird species’ suitability as a host for ticks. Conclusions: The data and results published here will contribute to a growing body of literature and information on bird-tick interactions and will help elucidate patterns of tick and tick-borne pathogen geographic expansion

DEMOGRAPHIC RESPONSE OF GOLDEN-WINGED WARBLER TO HABITAT MANAGEMNET ACROSS A CLIMATE CHANGE GRADIENT IN THE CORE OF THE SPECIES' RANGE: 2013 SUMMARY REPORT

No new data were collected for this project during 2013 but the RWO was extended into 2014 to support graduate student Sean Peterson during thesis completion and manuscript preparation. That thesis was successfully defended in November 2013, and the final thesis will be submitted to the University of Minnesota in early 2014 and disseminated to all cooperators as a Final Report for this project in 2014 along with all other published products. This 2013 annual report summarizes completed products and plans for additional data analysis, manuscript preparation, and publication in refereed outlets. So far we have produced 11 manuscripts from this project, of which 4 are published, 1 is in press, 4 are in review or revision, and 2 will be submitted for review in January 2014. We are organizing data and conducting analysis for 5 additional manuscripts. A second graduate student, Gunnar Kramer (supported on a separate RWO) will produce 2 of those manuscripts as part of his thesis. During 2013, we presented results from this project in 8 presentations; 5 at professional conferences, 2 at public venues, and 1 at a university. We have scheduled 2 additional professional presentations for 2014.Streby, Henry M; Peterson, Sean M; Kramer, Gunnar R; Andersen, David E. (2013). DEMOGRAPHIC RESPONSE OF GOLDEN-WINGED WARBLER TO HABITAT MANAGEMNET ACROSS A CLIMATE CHANGE GRADIENT IN THE CORE OF THE SPECIES' RANGE: 2013 SUMMARY REPORT. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/183613

Evaluating outcomes of management targeting the recovery of a migratory songbird of conservation concern

Background Assessing outcomes of habitat management is critical for informing and adapting conservation plans. From 2013–2019, a multi-stage management initiative, led by the American Bird Conservancy (ABC), aims to create >25,000 ha of shrubland and early-successional vegetation to benefit Golden-winged Warblers (Vermivora chrysoptera) in managed forested landscapes of the western Great Lakes region. We studied a dense breeding population of Golden-winged Warblers at Rice Lake National Wildlife Refuge (NWR) in Minnesota, USA, where ABC initiative management was implemented to benefit the species. Methods We monitored abundance before (2011–2014) and after (2015–2016) management, and we estimated full-season productivity (i.e., young recruited into the fall population) from predictive, spatially explicit models, informed by nest and fledgling survival data collected at sites in the western Great Lakes region, including Rice Lake NWR, during 2011 and 2012. Then, using biologically informed models of bird response to observed and predicted vegetation succession, we estimated the cumulative change in population recruitment over various scenarios of vegetation succession and demographic response. Results We observed an 32% decline in abundance of breeding pairs and estimated a 27% decline in per-pair full-season productivity following management, compared to no change in a nearby control site. In models that ranged from highly optimistic to progressively more realistic scenarios, we estimated a net loss of 72–460 juvenile Golden-winged Warblers produced from the managed site in the 10–20 years following management. Even if our well-informed and locally validated productivity models produced erroneous estimates and the management resulted in only a temporary reduction in abundance (i.e., no change in productivity), our forecast models still predicted a net loss of 137–260 juvenile Golden-winged Warblers from the managed area over the same time frame. Conclusions Our study site represents only a small portion of a massive management initiative; however, the management at our site was conducted in accordance with the initiative’s management plans, the resulting vegetation structure is consistent with that of other areas managed under the initiative, and those responsible for the initiative have described the management at our study site as successful Golden-winged Warbler management. Our assessment demonstrates that, at least for the only site for which pre- and post-management data on Golden-winged Warblers exist, the ABC management initiative is having a substantial and likely enduring negative impact on the species it purports to benefit. We suggest that incorporating region-specific, empirical information about Golden-winged Warbler—habitat relations into habitat management efforts would increase the likelihood of a positive response by Golden-winged Warblers

Variation in individual autumn migration and winter paths of Great Lakes red-headed woodpeckers (Melanerpes erythrocephalus)

Migratory movements of facultative migrants are poorly understood due to their irregular and often unpredictable occurrence. However, tracking such movements is important for understanding population dynamics, informing annual cycle conservation plans, and identifying possible cues of facultative migration. We used pinpoint GPS tags to track autumn and winter movements of migratory red-headed woodpeckers (Melanerpes erythrocephalus) to better understand migration frequency, timing, and routes for birds breeding in managed oak savanna systems in the North American Great Lakes region. Proportions of individuals migrating differed between the two sites, with 72% of the Ohio population migrating, while no individuals in the Minnesota population migrated. Of the Ohio birds that migrated, their movements were highly variable in distance and direction but generally occurred south of the breeding site. Wintering sites ranged from 111 – 218 km from the breeding site. Cover types occupied during migration and wintering were almost exclusively small patches of closed-canopy hardwood forest within agricultural matrices. We documented one-time movements in migratory and non-migratory individuals during the year that have not previously been described in facultative migrants. We found no evidence of a harness or marker effect on proportions of individuals migrating, migration return rates, or annual survival regardless of migration