The recovery of the endangered Cape Sable seaside sparrow (Ammodramus maritimus mirabilis) is of central concern to the ongoing restoration of the Florida Everglades. The Cape Sable seaside sparrow (CSSS) is a federally-endangered subspecies with a distribution restricted to the seasonally-flooded marl prairies of the Everglades. The loss or degradation of the sparrow’s marl prairie habitat due to past water management actions in South Florida has led to a decline in the population raising major conservation concern.

The Comprehensive Everglades Restoration Plan (CERP) is the overarching plan to return a more natural quantity, quality, timing and distribution of water (i.e., ‘getting the water right’) to the Everglades. Under this plan, ‘getting the water right’ is thought necessary to facilitate recovery of a suite of threatened species, including the CSSS. With this in mind, long-term research and monitoring on the sparrow has provided key information for both potential measures to help achieve recovery goals and real-time feedback so that managers charged with making seasonal water flow decisions have relevant information to do so. During 2015, Ecostudies Institute continued to lead CSSS monitoring efforts to provide the information necessary to aid in the recovery of this endangered species.

The Central Everglades Planning Project (CEPP) is the next generation of proposed projects to be implemented under CERP. One goal of CEPP is to identify and plan for projects on land already in public ownership to allow more water to be directed south to the central Everglades, Everglades National Park (ENP) and Florida Bay. Although this project is expected to produce large-scale hydrological benefits, there is also trepidation about its potential impact on endangered species, including the CSSS, whose range is extremely limited and population very small.

The goal of this project is to continue monitoring of CSSS populations found in ENP, and on adjacent lands managed by the South Florida Water Management District (SFWMD). With planning and recovery discussions for this endangered species expected to continue over the next year, this project will maintain continuity with previous research and monitoring, and begin to evaluate and consider previously recommended and new opportunities for recovery. During 2015, the specific monitoring objectives of this project were: 1) to continue ongoing monitoring in CSSS subpopulation A, which is considered perhaps the most vulnerable subpopulation, 2) compare demographic parameters with those from a high-quality reference subpopulation (subpopulation B), and 3) to assess the effects of the SFWMD’s C-111 Spreader Canal Project on subpopulation D which is located outside the boundary of ENP. We are also currently developing a spatially-explicit population estimator using available long-term data in order to derive a more accurate range-wide population estimate for the CSSS than is presently available. During 2016, our monitoring objectives will remain the same; however, we plan to expand our research to cover more study areas in other parts of the subspecies’ range.

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Key Findings

Below we report some key findings from our 2015 first field season monitoring Cape Sable seaside sparrows in Everglades National Park and adjacent lands. In 2015, we monitored sparrows breeding in three subpopulations (A, B and D). Our main study plots were approximately 1.6 km2, 0.7 km2 and 1.6 kmin subpopulations A, B and D, respectively.

  • The density of sparrows remained substantially lower in our study plot in subpopulation A (8.8 adults/km2) compared to subpopulation B (50.0 adults/km2). In total, we located 14 adults (8 males, 6 females) in A and 34 adults (18 males, 16 females) in B. Our results indicate stable numbers in subpopulation A in 2015, while numbers in subpopulation B increased marginally.
  • Subpopulation D, located outside of the boundary of ENP, reports the lowest density of sparrows (7.5 adults/km2) of the three sparrow subpopulations monitored. We observed only 12 adults (11 males, 1 female) in D in 2015. This represents a decrease in both male and female sparrows from 2014.
  • Demographic parameters were generally lower in subpopulation A compared to those in subpopulation B. We monitored 12 nests in A and 31 nests in B, and observed a substantially lower hatch rate in A (55%) compared to B (71%), which has been a consistent trend in recent years.  Overall productivity remained substantially lower in A (6 chicks fledged, 1.0 chicks/breeding pair) compared to B (23 chicks fledged, 1.5 chicks/breeding pair). We only monitored 3 nests from 1 breeding pair in subpopulation D; all hatched but only 1 nest fledged (2 chicks). The return rate of previously color-banded adult sparrows was also substantially lower in A (54%, n = 7) compared to B (80%, n = 24). Subpopulation D reported a strong return rate for this subpopulation (62%, n = 8).
  • Multi-brooding is thought to be an important factor for CSSS population viability. In 2015 we observed no multi-brooding in small sparrow subpopulations A or D continuing a trend observed in past breeding seasons in this and other small sparrow subpopulations. In contrast, we observed multi-brooding in 20% of the breeding pairs in subpopulation B.
  • Dispersal between CSSS subpopulations is known to occur, but is quite rare. During 2015, we documented no between subpopulation dispersal events.

Education

 Ecostudies Institute Reports and Publications

  • Virzi, T. and M.J. Davis. 2016. C-111 Project & Cape Sable Seaside Sparrow Subpopulation D – Annual Report 2016. Report to the South Florida Water Management District, West Palm Beach, FL. {PDF}
  • Virzi, T., M.J. Davis and G. Slater. 2016. Recovery of Cape Sable Seaside Sparrow – Subpopulation A. Report to the U.S. Fish & Wildlife Service (South Florida Ecological Services Unit, Vero Beach, FL). {PDF}
  • Virzi, T., M.J. Davis and G. Slater. 2015. C-111 Project & Cape Sable Seaside Sparrow Subpopulation D – Annual Report 2015. Report to the South Florida Water Management District, West Palm Beach, FL. {PDF}
  • Slater, G., M.J. Davis and T. Virzi. 2014. Recovery of the Endangered Cape Sable Seaside Sparrow in Everglades National Park: Monitoring and Setting Priorities. Final Report to the U.S. National Park Service (Everglades National Park, Homestead, FL). {PDF}
  • Virzi, T. and M.J. Davis. 2014. C-111 Project & Cape Sable Seaside Sparrow Subpopulation D – Annual Report 2014. Report to the South Florida Water Management District, West Palm Beach, FL. {PDF}

Further Reading

  • Virzi, T. and M.J. Davis. 2013. Recovering Small Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis) Subpopulations: Breeding and Dispersal of Sparrows in the Everglades. Final Report to the U.S. National Park Service (Everglades National Park, Homestead, FL). {PDF}
  • Virzi, T. and M.J. Davis. 2013. C-111 Project & Cape Sable Seaside Sparrow Subpopulation D – Annual Report 2013. Report to the South Florida Water Management District, West Palm Beach, FL. {PDF}
  • Virzi, T., R.L. Boulton, M.J. Davis, J.J. Gilroy and J.L. Lockwood. 2012. Effectiveness of Artificial Song Playback on Influencing the Settlement Decisions of an Endangered Resident Grassland Passerine. The Condor 114(4): 846-855. {PDF}
  • Gilroy, J.J., T. Virzi, R.L. Boulton and J.L. Lockwood. 2012. A New Approach to the “Apparent Survival” Problem: Estimating True Survival Rates from Mark-Recapture Studies. Ecology 93(7): 1509-1516. {PDF}
  • Gilroy, J.J., T. Virzi, R.L. Boulton and J.L. Lockwood. 2012. Too Few Data and Not Enough Time: Approaches to Detecting Allee Effects in Threatened Species. Conservation Letters 5: 313-322. {PDF}
  • Virzi, T. and M.J. Davis. 2012. Recovering Small Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis) Subpopulations: Breeding and Dispersal of Sparrows in the Everglades. Report to the U.S. National Park Service (Everglades National Park, Homestead, FL). {PDF}
  • Virzi, T. and M.J. Davis. 2012. C-111 Project & Cape Sable Seaside Sparrow Subpopulation D – Annual Report 2012. Report to the South Florida Water Management District, West Palm Beach, FL. {PDF}
  • Lockwood, J., R. Boulton, T. Virzi, J. Gilroy and M. Davis. 2012. Recovering Small Cape Sable Seaside Sparrow Subpopulations: the Breeding and Dispersal of Sparrows in the Eastern Everglades. Final Report to the U.S. National Park Service (Everglades National Park, Homestead, FL). {PDF}
  • Boulton, R.L., B. Baiser, M.J. Davis, T. Virzi and J.L. Lockwood. 2011. Variation in Laying Date and Clutch Size: the Everglades Environment and the Endangered Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis). The Auk 128(2): 374-381. {PDF}
  • Virzi, T., J.J Gilroy, R.L. Boulton, M.J. Davis, K.H. Fenn and J.L. Lockwood. 2011. Recovering Small Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis) Subpopulations: Breeding and Dispersal of Sparrows in the Everglades. Report to the U.S. National Park Service (Everglades National Park, Homestead, FL). {PDF}
  • Virzi, T., M.J. Davis, J.P. Sah, M.S. Ross and P.L. Ruiz. 2011. C-111 Project & Cape Sable Seaside Sparrow Subpopulation D: Baseline Data on Sparrows, Vegetation and Hydrology – Annual Report 2011. Report to the South Florida Water Management District, West Palm Beach, FL. {PDF}
  • Virzi, T., J. Lockwood, J. Gilroy, M.J. Davis, K.H. Fenn, B. Baiser and R.L. Boulton. 2010. Detailed Study of Cape Sable Seaside Sparrow Nests and Causes of Nest Failure & Conspecific Attraction and the Recovery of the Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis). Final Report to the U.S. Fish &Wildlife Service (South Florida Ecological Services, Vero Beach, FL). {PDF}
  • Lockwood, J., T. Virzi, R.L. Boulton, J. Gilroy, M.J. Davis, B. Baiser and K.H. Fenn. 2010. Recovering Small Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis) Subpopulations: Breeding and Dispersal of Sparrows in the Everglades. Report to the U.S. Fish &Wildlife Service (South Florida Ecological Services, Vero Beach, FL) and the U.S. National Park Service (Everglades National Park, Homestead, FL). {PDF}
  • Virzi, T., J. Lockwood, R.L. Boulton, and M.J. Davis. 2009. Recovering Small Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis) Subpopulations: Breeding and Dispersal of Sparrows in the Everglades. Report to the U.S. Fish & Wildlife Service (South Florida Ecological Services, Vero Beach, FL) and the U.S. National Park Service (Everglades National Park, Homestead, FL). {PDF}

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