RiparianRiparian Zone Retreat Zone Retreatand Population Studiesand Population Studies

Tara Matson,Tara Matson,

Honors Biology II,Honors Biology II,

and Period 1.and Period 1.

Niche of the Red-Tailed HawkButeo jamaicensis

• Found in the United States, Canada, Mexico, and Latin America, these birds can live practically anywhere as long as there is open space and high perches. They can live in parks, forests, fields, pastures, grasslands, and scrub deserts. They build their nests at the edge of the forest or in large trees surrounded by open fields.

• Red-Tailed Hawks are carnivores, eating small rodents, rabbits, reptiles, and even some other birds. They will also feed upon already dead (carrion) animals. Great Horned Owls and Corvids are virtually the hawk’s only predators.

• When hunting, the hawk usually hunts from a perch. They watch and wait until they see their intended prey, then they dive, using their sharp, powerful claws as weapons.

Factors which Affect Birth Rate of the Red-Tailed Hawk

• They usually mate in late winter or early spring.

• When they pick a mate, it is usually for life. They will get a new mate if the original one dies. The male and female do an “air dance” when they are courting, then they perch to do the actual breeding. They build a nest together, and use the same nest for as long as they can.

• Eggs are laid about six to eight weeks after mating.

• Females lay one to five eggs every other day during the first week of April.

• The female lays on the eggs, while the male brings her food. Sometimes the male will sit in the nest, but it’s only for a short time. When the eggs hatch, the male brings food to the female and chicks, and the female tears it up for her young to eat.

• Red-Tailed Hawks start breeding between two and three years of age.

Factors Which Affect the Death Rate of the Red-Tailed Hawk

• The Red-Tailed Hawk is usually the hunter, not the hunted. They only have a few predators including the Great Horned Owl and Humans.

• The Hawk can live up to 21.5 years in the wild and some of the ones held in captivity lived to be 29.5 years old.

• If there gets to be too many Red-Tailed Hawks in one place, they will become overpopulated. The fight for food will become more difficult, and the hawks will turn on one another.

Food Chain Red-Tailed HawkThe producer here is the grass. The grass is an auxotroph, so it makes it’s own food. The grass is then eaten by the primary consumer, the rabbit, who is also a herbivore. He only eats plants. The rabbit gets eaten by the Red-Tailed Hawk, the secondary consumer and carnivore. And, if unlucky enough, the Red-Tailed Hawk can get eaten by the Great Horned Owl, the tertiary consumer.

Producer

Autotroph

Primary Consumer

Herbivore

Secondary Consumer

Carnivore

Tertiary Consumer

Carnivore

Food Web of Red-Tailed Hawk

This is a food web that includes the Red-Tailed Hawk. These animals are not limited to the other organisms that they are linked to.

Herbivore

Producer Omnivore

CarnivoreCarnivore

Producer

CarnivoreHerbivoreHerbivore

Omnivore

Producer

Population Sampling Techniques

• Mark and Recapture As you capture a certain type of organism, mark it in a way as to not harm the critter. Then release the organisms back into their environment. Come back later and recapture the animals. Count how many are marked and how many are unmarked.

• To find the population of the Red-Tailed Hawk, researchers use tagging. The put a tag on the ankle of the bird and then let it go. Later on they recapture the birds.

Stream Quality Data & AnalysisStream Quality Data & Analysis• This graph shows how many organisms

from each class that our whole class caught. Class I organisms are the pickiest with the water that they live in, so an abundance in these organisms means that the stream is in good health. Class III organisms can live in pretty icky conditions, so if there are a lot of things like scuds and leeches and not so many stoneflies, then the stream might not be in such good shape.

• The Red-Tailed Hawk, although not an aquatic animal, would need the stream to be in good health, with lots of Class I organisms. The hawk needs clean drinking water, and it hunts other animals that would need a healthy stream to survive (i.e. Fish).

• If most of the organisms that we caught were Class III, then the stream would be in poor condition. The Red-Tailed Hawk wouldn’t have drinking water, and other animals would migrate in search of fresher, cleaner water.

Water Testing Data & AnalysisWater Testing Data & Analysis• Dissolved Oxygen-the amount of dissolved oxygen

present in the water. This oxygen is used by organisms to breathe. A relatively high level means that there is more air to breath, which is good. The phosphate and nitrate levels measure how much phosphate and nitrate are present. Too much of either of these things can have harmful effects on the stream. pH measures “potential hydrogen” and the pH determines whether or not the stream is neutral, acidic, or basic (alkaline).

• The ideal range at Powdermill for each category are as follows: Nitrate and Phosphate Levels 0, Dissolved Oxygen 10-15, and pH 6.5-7.5.

• If the hawk lived by the stream, he would have cleaner water to drink from, and he would most likely find more animals to hunt. The marsh and the mine would provide less decent drinking water.

• The temperature and turbidity of the water also has to be in good condition. All three water samples had no turbidity, so organisms could technically breathe and plants could photosynthesize. The temperatures all fell between 55-70˚ F. The temperature affects how well the stream hold dissolved oxygen.

0

20

40

60

80

100

120

140

160

180StreamMarshMine

Nitrate Level

DissolvedOxygen

pH PhosphateLevel

Soil Testing & AnalysisSoil Testing & Analysis

0

2

4

6

8

10

12

14

16

18

20

pH Potash

Phosphorus

Nitrogen

Riparian

School Site

• pH, potash, phosphorus, & nitrogen are important to the soil because these nutrients play a vital role in plant growth and metabolism and pH helps the plants in the soil utilize the nutrients in the soil.

• The ideal range for pH is 4-7.5 or 8. Nitrogen and Phosphorus should be at trace levels and Potash should be at a higher level.

• If the levels are out of their range, bad things could happen. A basic pH could cause plants not to grow. Too much nitrogen and phosphorus can cause plants to grow too much.

Positive and Negative Factors• The healthy stream quality of Powdermill meant that more organisms would be living in the stream. The more organisms in the stream, the more organisms in the riparian zone.

•The soil conditions would affect the plants. The plants would effect the herbivores. Since the red-tailed hawk eats some herbivores, any negative impact on them would negatively impact the hawk.

• The agricultural run-off and abandoned mine drainage are two of the biggest pollutes to PA streams. Farmers can build buffers and we can filter AMD water with settling ponds in order to clean up steams. Clean streams means more diversity in the riparian zone…which we want.

Conclusion

•I had no idea that hawks had enemies, such as the Great Horned Owl.

• I thought finding and identifying all the animals in the stream was really interesting.

• I really liked researching the Red-Tailed Hawk…I think that I would enjoy researching other animals and organisms.

Works Cited•"Hawk." Encyclopedia.com. HighBeam Research, Inc., n.d. Web. 12 May 2010. <http://www.encyclopedia.com/topic/hawk.aspx>. •Dewey, Tanya. "Buteo jamaicensis." Animal Diversity Web. University of Michigan Museum of Zoology, n.d. Web. 12 May 2010.<http://animaldiversity.ummz.umich.edu/site/accounts/information/Buteo_jamaicensis.html>. Roetzel, Jim. "Red-Tailed Hawk." Study of Northern Virginia Ecology. Island Creek Elementary School, n.d. Web. 12 May 2010. <http://www.fcps.edu/islandcreekes/ecology/red tailed_hawk.htm>.