Abstract:

Seaside Sparrow (Ammospiza maritima) nests were monitored every 2-4 days each year 2012-2017 between 15 March and 30 June near Bay Batiste and Bay Sansbois, Plaquemines Parish, Louisiana. Vegetation data associated with each nest include plant stem density height profiles and estimates of the percent coverage of common marsh plant species. Vegetation surveys for each nest were paired with a similar vegetation survey completed for a randomly selected point within 8-25 m of each nest. Nest data are formatted for analyses using the logistic exposure method to include the day of nest initiation, the day the nest was last checked, the number of exposure days, and the fate of the nest.

Suggested Citation:

Woltmann, S.. 2020. Seaside Sparrow nest survival and vegetation data from Plaquemines Parish Louisiana, 2012-04-25 to 2017-06-24. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-w5g6-e664

Purpose:

The purpose of these data is to ask whether nest survival differed on plots originally exposed to oil from the Deepwater Horizon spill; we additionally use these data to explore whether or how nest survival rates differ by bay or year, or depending on vegetation characteristics.

Data Parameters and Units:

Worksheet Nest Data Dictionary: Contains detailed descriptions of variables in worksheet “Nest_Survival_Data_2012-2017”. Worksheet Nest_Survival_Data_2012-2017: Contains data used to estimate daily survival rates of nests for all 6 years of the study. Detailed variable descriptions are located on the worksheet “Nest Data Dictionary.” Worksheet Vegetation Data Dictionary: Contains detailed descriptions of each data parameter found in worksheet “Random_Veg_Points_2012-2017”. Worksheet Random_Veg_Points_2012-2017: Contains raw vegetation structure data associated with sparrow nest survival studies. These non-nest points are paired with the measurements for each actual nest in worksheet “Nest_Survival_Data_2012-2017” by using the “Nest_Pt_ID” and “Veg_Pt_ID” identifiers. Live and dead stems were counted within a 1-meter square (from 0-120 cm in each corner of the square) and percent vegetation cover type in the 1-meter square and a 5-meter square. Detailed variable descriptions are located on the worksheet “Vegetation Data Dictionary.” Values of “9999” or “NA” indicate missing data, depending upon the parameter.

Methods:

Nest Survival Assessments Seaside Sparrow nests were monitored from 15 March to 30 June 2012-2017, which overlaps with the majority of Seaside Sparrow nesting season in the region. The search effort was constant (person-search-hours) across plots within years, but varied among years due to personnel constraints. Nests were located by systematic searching and using behavioral cues from adult Seaside Sparrows. Seaside Sparrows in our study have 12-day incubation and 9-day nestling periods, and mode of 3-egg clutches. Nests were monitored every 2-3 days until fate could be determined. Nests were classified as successful if a nest fledged at least 1 nestling as determined by: (1) sighting of fledglings near the nest; (2) adults carrying food to the area post-fledging; (3) begging sounds of fledglings in the surrounding vegetation; or (4) the presence of fledgling fecal matter in or on the rim of the nest or on the surrounding vegetation. Nests were classified as failed if: (1) eggs or nestlings disappeared from the nest before fledge day with no evidence of early fledging; (2) eggshells or nestling remains were present; or (3) nests were torn, tilted, flooded or otherwise destroyed before the fledge date. Unknown fate was assigned to nests that were empty near the fledge day without conclusive evidence of fledging or predation. Vegetation Measurements Once nests were empty, vegetation characteristics were measured for each nest following a protocol developed for Seaside Sparrows. A pole marked in 20-cm increments was used to measure vegetation and nest height, and the number of stems (live and dead) touching the pole within 20-cm sections was recorded at the 4 corners of a 1m2 frame placed around the nest. Percentage of the ground cover was estimated for each plant species, and for open water, detritus, and bare ground within 1 m2 and 5m-radius around the nest. For each nest, a random point was chosen within 25 m from the nest to represent a potential nest site not chosen by the female but still within the male’s territory. The same vegetation survey was conducted for random points.

Individual Files: