This research examined the behavior of avian scavenger bone dispersal in a New England environment. The furthest distance that avian species can carry bone elements can be used by search investigators by providing possible distances maximum dispersal. The sizes of bones dispersed by avian species provides context on how bone elements differing in size are transported from the initial site of deposition. The project utilized two locations with elements of varying sizes (large, intermediate, and small) with tracking tags attached to determine the distance and pattern of scavenger displacement. Scavenging was also recorded with motion-sensing game cameras that allowed for differentiation between which species scavenged on which elements, allowing for the distance carried to be associated with individual species. The most common avian scavengers were the northern cardinal (Cardinalis cardinalis), downy woodpecker (Dryobates pubescens), and blue jay (Cyanocitta cristata). The furthest element that was displaced and recovered was a pig rib approximately 62 meters from its initial placement location and it was moved by a crow (Corvus brachyrhynchos). The second furthest element displaced was a pig rib moved approximately 41.5 meters by a Cooper’s hawk (Accipiter cooperii). In addition, six other elements were removed from the platform by birds and not recovered due to possible displacement outside of the search radius and tracking application radius.
Overall, 55.0% of elements were recovered within 1 meter of their initial placement location. For elements dispersed under 1 m, Rayleigh z-statistical tests (z =1.328; α = 0.05) for the site location in a wooded area indicated that directionality was not statistically significant, while the location in the wetlands was determined to be statistically significant (z = 20.656; α = 0.05). In addition, a Watson’s U2 Two-Sample Test of Homogeneity (U2 = 0.374) revealed the two groups of average directions are significantly different at α = 0.05. This indicates a difference in direction of displacement between the platforms. For Platform 1 (forested location), the results of the Mann-Whitney U-Test (z = -2.638) indicated that the distances of displacement between the spring and summer seasons are significantly different between the two seasons at α = 0.05. For Platform 2 (wetland location), the results of the Mann-Whitney U-Test (z = -0.859) indicate the distances of displacement between the two seasons were not significantly different between the two seasons at the α = 0.05 value. In addition, Kruskal-Wallis H tests revealed that there was no statistically significant difference between the platform location and the number of site visits for the majority of species. Only two species, cardinals (z = -2.04; α = 0.05) and song sparrows (z = -2.208; α = 0.05), were determined to have a statistically significant difference between the location and the number of site visits.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/48169 |
| Date | 22 February 2024 |
| Creators | Duda, Cooper M. |
| Contributors | Pokines, James, Moore, Tara |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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