sfgate.com
Rob Lee
Whether the Giants are winning games in big fistfuls, or can’t produce as much offense as a foul-mouthed grandmother, there’s always a good reason to go to their ballpark. I’m not talking about the starlings foraging in the outfield grass, or the hordes of Western gulls that begin gathering faithfully during the seventh-inning stretch (although the best seats for my proposed entertainment are in the upper deck, with the gulls).
I’m speaking of the barn swallow and the white-throated swift, foraging on all those beer-crazed bugs rising off the crowd. While these birds are seemingly quite similar — long, swept-back wings, the aerodynamics of great fliers — the swallow is a song bird and the swift is not; actually more closely related to hummingbirds.
Sitting high in this bird observation platform, formerly known as the Giants’ home, you’ll notice that the two birds have different flying techniques. The swallow cuts a graceful, complicated swath through the air, constantly maneuvering to pick off one insect after another, while the swift is just that; flashing under the stadium lights like a jet, using a few quick, powerful strokes of its wings and then a short glide, eating the tiny insects — “aerial plankton” — in its path.
The white-throated swift may be the fastest bird in North America, once estimated to have fled a swooping falcon at more than 200 mph. It could easily keep pace with, inspect and then pass a soaring Barry Bonds homer. Both of these birds have wings “built for speed,” but the swallow has slender, flexible wing bones suitable for its elegant flight, while the swift has shorter, more massive bones (and long primary feathers), with which it can achieve the stiff, superfast wing beats that give it surpassing speed.
Swallows typically fly lower to the ground, pursuing insects (their hard work providing a very nutritious diet), while swifts fly high, on a line, and much longer distances, hunting for clouds of anthropoids to charge through repeatedly. While the swift’s flight uses less energy, it also yields less nutrition in the types of insects caught. (Swifts typically fly more than 500 miles a day, and, as they are long-lived for small birds — larger swifts may live more than 20 years — well over a million miles in their lifetime.)
Both birds do nearly everything in flight, including drinking, bathing, courting, and, among swifts, copulating. Some swifts, after mounting high in the sky, are even thought to sleep in flight.
Flying is so central to the lives of these birds that the swallow can only walk with difficulty and the swift can’t walk at all. Swallows have tiny, weak legs and feet that only allow perching on such things as wires or thin twigs. Swifts’ legs are virtually nonexistent, but they have tiny, strongly clawed feet, all four toes facing forward, with which they can hang on vertical surfaces, such as cliffs or buildings.
Barn swallows are a really lovely bird, artistically colored in blue, rust and buff with a long swallowtail, while the swift is basic black and white.
Barn swallows raise four to five chicks in their mud-and-grass cup nest, usually affixed under the eaves of a building or beneath a bridge. (These swallows have used human structures for nesting so widely, and for so long, their natural sites are virtually forgotten.) White-throated swifts raise a similar brood in very inaccessible crevices in cliffs, and sometimes buildings. Gathering twigs on the wing from dead trees, they build a cup nest, which they cement in place, and together, with saliva.
The close proximity to people with which these swallows consistently nest makes them one of the easiest nesting birds to observe, while this swift is just the opposite, with relatively little known about its nesting behaviors.
Both birds migrate, but the white-throated swift doesn’t go very far, usually not beyond the Southwest. The barn swallow is a champion long-distance migrator, some birds going 7,000 miles each way. Both of these species are social, usually found in small to large flocks, although the individuals I saw at the ballpark were alone.
I can’t promise the birds will show up when you go to a game, but if they do, it will be a joy to watch their two styles of mastery above the crowd, the two species, in a way, mirroring the combination of relaxation and intensity that characterizes baseball.
June 21st, 2006
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.
June 21st, 2006