Riparian Zone Retreat and population studies Cora Weaver, Biology II, Period 1.
Niche of the Great Horned Owl (Bubo virginianus) <ul><li>Because the Great Horned Owls are so widespread they have adapted to many habitats. But the majority of their habitat consists of treed areas like forests, woodlands and shrub lands. </li></ul><ul><li>The owl eats a variety of small to medium mammals, birds, amphibians, reptiles, fish and insects. It does not have many predators because is so large and many animals will not challenge it. </li></ul><ul><li>They hunt at dusk and during the night from a perch or while flying low over the ground. </li></ul><ul><li>Their wingspan can range from 40 to 60 inches; with a body of only 18 to 27 inches. The females are usually larger then the males. </li></ul>
Factors which Affect Birth Rate of the Great Horned Owl <ul><li>Most Great Horned Owls mate for life; they pair up in late winter to reproduce. </li></ul><ul><li>Typically the owl only reproduces once a year, raising only one brood a season. </li></ul><ul><li>The gestation period lasts about 25 to 35 days. </li></ul><ul><li>The amount of eggs laid usually ranges from 2 to 6 every time. </li></ul><ul><li>Both male and female owl care for the young; incubating the eggs, feeding them and protecting the territory. The care for the young until they are old enough to fly and learn how to fend for themselves. </li></ul><ul><li>The breeding season ranges from as early as December to as late as July. </li></ul>
Factors Which Affect the Death Rate of Assigned Animal <ul><li>As far as relationships go, that the owl is involved in, competition is a big one when it comes to territory. But the biggest relationship it is involved in is predator-prey, because it is a carnivore and always hunts its prey </li></ul><ul><li>The Great Horned Owls typically live about 13 years in the wild, but can live up to about 30 if in captivity. </li></ul><ul><li>The owl is commonly victim to parasitic infections and is found to be among the top reasons for death. Parasites found in the blood and liver are the most common to be found when studies have been done upon owl carcasses. </li></ul><ul><li>Over-population would harm the owl because of the intensity of competition. Since they do not have very many predators and are very territorial it is not good for large numbers of these birds to end up in the same area because fights would break out frequently and be a serious issue for death. </li></ul>
Food Chain of a Great Horned Owl Producer Autotroph Primary Consumer Omnivore Secondary Consumer Carnivore Tertiary Consumer Carnivore
Population Sampling Techniques <ul><li>Marking and recapturing is a good population sampling technique, this is when you capture the organisms and mark them in a way and then release them back into their habitat. The following day they repeat the process to calculate the population from the data. </li></ul><ul><li>The type of population sampling technique used on the Great Horned Owl is the marking and recapturing on mentioned above. They put tags on the birds legs that have numbers to be able to identify when the bird was captured the first time. </li></ul>
Stream Quality Data & Analysis <ul><li>The graph helps show the quality of the water in the stream, by showing how many organisms were caught and put under which Class they belong. </li></ul><ul><li>Each Class of Organisms represents a different level of stream quality; going from the best to the most polluted, Class I to Class II. Since there were a great deal of Class I organisms found it shows that the water quality of the steam has good water quality. </li></ul><ul><li>The good water quality found in the stream would only benefit the Great Horned Owl. Other animals would come to the stream for clean water, or for their habitat, which is when the owl could find its next possible meal. </li></ul><ul><li>If the majority of the organisms found had been in Class III, that would mean that the stream was polluted. Which in turn would affect the other organisms that need clean water to drink and the plants that need clean water would die. Therefore the animals needing to eat those plants would suffer because the plants are suffering. </li></ul>
Water Testing Data & Analysis <ul><li>For a healthy steam, the nitrates and phosphates should be zero to none, the pH should be neutral and around 7.0, have a decent amount of dissolved oxygen for the organisms to survive, around 6-10. </li></ul><ul><li>The ideal range for Nitrates and Phosphates at Powdermill is zero. Dissolved oxygen should be around 6-10, indicating a healthy stream. The pH level should range from 6.5 to 7.5 to support life. If the levels of any of these get too high or low, then the steam is polluted and can kill off the organisms. </li></ul><ul><li>The owl would obviously survive better when its habitat is near the healthy steam. There would be more organisms there for the owl to thrive on because the can survive the best with the steam because it has the right amount of dissolved oxygen and low phosphate and nitrate levels. The plants will also be the healthiest here which is important when it comes to the owl’s need for shelter. </li></ul><ul><li>The temperature of the waters effect how much dissolved oxygen can be maintained, and the amount of oxygen the water can hold is important for the organisms living in the water. The turbidity can affect the predator-prey relationships and also clog the gills of organisms if it gets high. </li></ul><ul><li>.. </li></ul>
Soil Testing & Analysis <ul><li>Nitrogen is important in the soil for plants to have a proper functioning metabolism. Phosphorus is the most important nutrient when it comes to root formation. Potash helps with flowering and is needed in photosynthesis to make sugars. The pH level is important for specific plants to control how well they can absorb nutrients in the soil. </li></ul><ul><li>The ideal range for pH levels in the soil go from highly acidic, at 4.0, to slightly alkaline, at 7.5 to 8. The ideal ranges for potash, phosphorous and nitrogen are medium levels. </li></ul><ul><li>If the nitrates and phosphates are too high they can actually kill plants growing in that area because they cannot absorb the nutrients in the correct way. </li></ul>
Positive and Negative Factors <ul><li>The stream water is best for the owl because it is the healthiest and it will be able to get the most amount of organisms there to hunt, because they need the healthy water. The marsh and mine water would not be as good for the owl as far as a habitat and a place for hunting go. They need healthy trees to next in and if they eat an organism that uses the unhealthy water, it will not be good for the owl because then they will receive whatever the other organism consumed which would harm the owl if it was bad for the first organism. </li></ul><ul><li>The soil conditions must be good for the Great Horned Owl to survive. The soil will affect the plants in the area, including the trees which is the major part of the owl’s habitat. </li></ul><ul><li>Factors that positively affect the riparian ecosystem are the Class I organisms and the levels of the pH, phosphates, nitrates, and potash. These all are factors that can keep the stream healthy and are a great way to check and make sure that the stream is staying healthy. </li></ul><ul><li>Factors negatively affecting the riparian ecosystem are abandoned mine drainage and farmland run-off. Both of these factors pollute the streams in PA. They put more nitrates and phosphates into the water which is not good for the organisms living there. They can also affect the pH level which will harm the organisms because they are not adapted to anything outside of their ideal pH level range. </li></ul>
Conclusion <ul><li>I learned that if you have too many nitrates and phosphates in the water it can cause the plants in the water to grow excessively which would end up using all of the oxygen in the water; causing the fish to actually suffocate. </li></ul><ul><li>I found the most interesting part of the project to be when we went to Powdermill and had to identify the organisms we collected because I identified a dragonfly nymph when no one else in the group could figure out what it was. </li></ul><ul><li>As far as an environmental topic goes, that I would like to do further research on, I think it would be interesting to do more of a marine biology topic involving the organisms because it seems like you could get more in depth with different areas. </li></ul>
Works Cited http://www.owlpages.com/owls.php?genus=Bubo&species=virginianus http://www.encyclopedia.com/topic/owl.aspx http://www.encyclopedia.com/article-1G2-2830100318/birds-prey.html
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