Site: Patuxent Wildlife Research Center With the Bird Phenology Program (BPP) Building 308, Center Road, Beltsville MD Purpose: At BPP, I do a variety of things including sorting, scanning and refile-ing bird migration cards All cards are from the 1880s-1970s Mentor: Jessica Zelt She is the Program Coordinator of BPP.
The study conducted, researched bird arrival dates and whether elevation patterns affected their flight was studied in the states of New jersey, Maryland, Delaware, Pennsylvania and Virginia Birds Studied include Wilsonia citrina, (Hooded Warbler) Setophaga ruticillla (Amerian Redstart), Dendroica petechia (Yellow Warbler) and Dendroica fusca. (Blackburnian Warbler) Later on other variables such as Latitude and Year were added This topic was selected because at BPP an abundance of bird migration cards are available and Ms. Jessica Zelt suggested these species because they are neo-tropical migrants; traveling from southern and Central America to breed in Northeastern America.
A birds behavior is heavily dependent on the state and condition of the earth. Birds are very responsive to any slight fluctuations, changes or differences in the environment because those are their cues as to when to start, stop and travel during migration. Studying how birds have been affected by elevation will provide insight on how/whether the earth has or has not been affected over time.
Example of Bird Migration card Few of the cabinets that store migration cards Me holding a bird, during the field visits Photos Courtesy of Jessica Zelt
How Does elevation affect Bird migration arrival dates ? American Redstart/ Setophaga ruticilla http://sdakotabirds.com/species_pho tos/american_redstart_2.htm
It is predicted that the higher in elevation a certain area is, the longer it takes the bird to travel and thus causes a later arrival date because if the Julian Date increases then the elevation has also increased. Null: If the Julian date decreases then the elevation has decreased and there is no correlation between the two variables. Yellow Warbler/ Dendroica petechia http://www.pbase.com/dadas115/ image/129002746
Migration records from New Jersey, Pennsylvania, Maryland, Delaware, and Virginia from the Bird Phenology Program were scanned onto the desktop using Adobe Standard 7.0. All Bird cards were transcribed into Microsoft Excel, and the altitude, latitude, and longitude was also found using http://www.gpsvisualizer.com/geocoder/ and transcribed into excel.http://www.gpsvisualizer.com/geocoder/ All of the data was sorted according Julian Date. Data with migration dates after May 20th, Julian day 120 were deleted. Pivot Charts and Histograms were made for each state and bird species, and the number of times a Julian date occurred was graphed. Various graphs made, like Julian Day vs. Altitude, Julian Day vs. Latitude and Year vs. Altitude, to analyze, organize, and view data. Program named Past.exe was downloaded to begin statistically analyzing data. Past.exe was used to find the p-value, r 2, slope, and intercept for the cumulative states of each species. Data was placed into a chart. Multiple regression tests were also utilized to analyze the surplus of data comparing Julian date to more than one independent variable. http://www.pbase.com/dadas115/ima ge/110560030 Wilsonia citrina /Hooded Warbler
Analysis of Julian Day Vs. Altitude Species# of RecordsSlopeInterceptP-valuer2r2 Wilsonia citrina36415.5-1808.60.9080.000 Setophaga ruticilla855-18.5-2088.40.0130.007 Dendroica petechia560-15.62014.70.0000.091 Dendroica fusca393-20.02718.40.0000.041
In studying how altitude affected the Julian date of arrival of the four different Neo-tropical migrants, a total of 2172 migration cards were scanned and analyzed. When the species were analyzed as a whole, all of the data was significant except for the Wilsonia citrina (Hooded Warbler). When the data was shown to be significant it was always extremely significant with P-values at less than 0.05. All of the data placed in the previous chart can also be viewed in the graphs to be shown.
Although the majority of the data did not support the hypothesis; many significant figures can be drawn from the graphs and charts compiled. The trend lines for Setophaga ruticilla, Dendroica petechia and Dendroica fusca displayed a weak negative correlation, supporting the null hypothesis. Wilsonia citrina did display a positive but weak correlation. The r 2 values are also very low for all tests. This shows that although the variables studied played a role, they were not the only thing affecting the arrival dates. Sheds light that the earth and climactic factors may also play a larger role than hypothesized. Overall the study provided a better insight and understanding of how the variables, mainly altitude, but also latitude, and year, played a role in later arrival dates.
In conclusion the hypothesis was not supported. It was reasoned that when birds fly, specifically the male, as it arrives to its site and area of breeding instead of landing at the first place it sees the male will look to higher ground, and a more secure habitat to settle. This helps ensure that when the female birds arrive looking for a mate they have the best chance of producing the healthiest offspring, and the likelihood of the survival of themselves and their offspring increases.
More research will be conducted at BPP in the near future to study the effects of many other climatic factors. Since elevation was not a key role in the four species tested, this study could also be run again except with using different bird species Future studies could research fall arrival dates instead of spring arrival dates. could also look at how birds have responded to climate changes over the years, with controversial topics such as global warming or even the cooling of the earth in past centuries. Repeat the same study except with a larger sample size, and/or different species.
I would like to thank my mentor, Jessica Zelt for always being positive and supportive and providing numerous resources throughout the whole study. I would like to thank Sam Droege, for always being like second mentor and helping out a lot with my statistics and always giving great direction for the next step in my project I would also like to thank my parents for their continuous support.