oas.ucok.edu
Eric Whelan
Abstract
Barn swallows, Hirundo rustica, are small migratory birds found almost anywhere. They stay in Oklahoma for nine months at a time and migrate to the south. They have two broods a breeding season. Their nests are made of soil, plants and other materials available to them. The objectives of my research were to find whether there was a positive correlation between mass in grams and percentage of organic matter, to find whether there was a positive correlation between diameter and percentage of organic matter. I collected the nests under the eaves of McLoud High School’s West building. The nest did not come down easily and many broke during collection. The nests were sorted for organic and other materials. They were mixed well in water and settled into distinct layers- sand, clay, and silt. They were classified into soil types. My hypothesis is that the mass in grams has a positive correlation with the percentage of organic matter, and the diameter has a positive correlation with the percentage of organic matter. My initial hypothesis was contradicted by the data collected. Neither showed any correlation.
Introduction
Barn swallows, Hirundo rustica, are small migratory birds that live in every continent except Antarctica and Australia. They spend mid January to September in Oklahoma. They spend winters in the Southern United States and Mexico.
Barn swallows have one to two broods every breeding season. The first brood of the season helps the parents care for the second brood of the season. They return and rebuild their nest every breeding season. The nest is primarily made of soil and plants and is built under bridges, eaves of buildings, and barns as the name implies. (1)
This summer I had the opportunity to attend Field Studies of Multidisciplinary Biology at the University of Oklahoma Biological Station. I developed an interest toward the animal kingdom (especially birds) and plant kingdom (especially grasses). Thus the objective of this project was to learn about the natural history of barn swallows by investigating the contents of the nest in terms of plants and animals that compose the nests. I also wanted to learn about the inorganic composition by classifying the soil type. I wanted to relate the size and mass of the nest in terms of percentage of organic material to size and mass to see if there is a positive correlation between size and percentage organic material and a positive correlation between mass and percentage of organic matter.
Methods and Materials
The nests were collected under the eaves of McLoud High School’s West building. They were cut down using a dissecting scalpel and placed in two paper bags. One bag for the north side of the building and one bag for the south side to keep the sides separate. The mass, in grams, of each nest was taken. The diameters of the nests were measured in centimeters; some nests were impossible to determine due to breakage during collection. Each nest was then taken apart and sorted for plants, animals, manure, feathers, and other materials. The nest was then placed in a beaker with water and mixed well in order for the remaining organic matter to float to the top and be collected by scraping the surface with a screen. The mixture was allowed to settle into 3 distinct layers-sand, clay, and silt. A soil classification pyramid (see Figure 1) was used to classify the soil. The organic mass was measured. The organic matter was sorted for grass spikelets, reproductive parts, seeds, small animals, feathers, and broad leaves. The organic matter was then identified (2,3,4,5). Dividing the grams of organic matter by the grams of total mass collected the percentage of organic matter was calculated.
Results
Of the 19 nests collected all contained organic matter; however, not all had identifiable features. Table 2 shows the species of plants that were found in each nest. The most common plant species found in the nests was Cynodon dactylon (2). Small acorns were found in nest 4. Small snail shells were found in nests 7 and 14. Parts of a cricket were found in nest 13. Nest 3 contained woodpecker, rock dove and American robin feathers. Nest 19 contained red tail hawk, Paris woodpecker, rock dove, and American robin feathers. No barn swallow feathers were found because barn swallows will not pluck their own feathers for the lining of the nest. Nest 3 contained carpet, tarp, plastic packaging, thread, and dental floss. Nest 7 contained horse hair. Nest 11 contained pieces of carpet. Nest 19 contained twine and cigarette packaging. Table 2 shows the plant species found in the nests, animals found in the nest, and other materials found in the nest. Of the 19 nests collected, 63.4% were soil type loam, 15.8 % were soil type sandy loam, 10.5% were soil type silty loam, and 10.5% were soil type clay loam. Table 1 shows diameter in centimeters, mass in grams, percent organic matter, soil type, number of plant species, number of animal species, and number of other materials.
Discussion of Results
My initial hypothesis that percentage of organic matter had a positive correlation with mass was contradicted. The mass and organic matter shows no correlation, positive or negative. The initial hypothesis that diameter and percentage organic matter had a positive correlation was also contradicted. They show no correlation. Figure 2 shows the correlation between mass in grams and the percentage of organic matter. Figure 3 shows the correlation between diameter in centimeters and percentage organic matter.
Acknowledgements
I would like to thank most of all Dr. Bruce Smith, for helping me tremendously with this project and keeping me on task. I would like to thank Paula Tolbert for always asking what she can do to help, staying hours after school to help and going out of her way to make this project so much easier. I would like to thank Dr. Mike Bay for his contribution to this project. I would also like to thank Jessica Schmidlkofer, Brad Story, Tyler Hill, Miranda Fetters, and Craig Hatfield.
