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Bird Diversity and Habitat. Experimental Design. Compare bird species in two habitats (U of A campus and Catalina Mountains) Do bird counts in these two areas and record the findings Statistical analysis to compare bird diversity between the two habitats. Hypothesis.

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Experimental design
Experimental Design

  • Compare bird species in two habitats (U of A campus and Catalina Mountains)

  • Do bird counts in these two areas and record the findings

  • Statistical analysis to compare bird diversity between the two habitats


  • Null Hypothesis: There is no significant difference in diversity between bird species in the Catalina Mountains and U of A campus

  • Due to the birds’ habitat, we think that we will see more pigeons and sparrows on the University of Arizona campus, and more varieties of birds such as cactus wrens, mourning doves, and quails off campus near the Catalina Mountains. (Rejecting the null hypothesis)

U of a campus description
U of A Campus Description

  • The bird counts were taken at various places throughout the University Campus.

  • Bird counts were taken at the Student Memorial Union, Arizona Sonora Dorm, Mall, Park Student Union, etc.

  • Landscape varied from desert plants to grass areas

Catalina mountain description
Catalina Mountain Description

  • Counts were taken near a wash near the Catalina Mountains

  • Desert landscape from low shrubs and brush to cacti and open terrain

Columba livia rock dove and common pigeon


Wild rock doves nest in crevices along rocky seaside cliffs, close to agriculture or open shrub vegetation.

In cities, the skyscrapers tend to take the place of their natural cliff surroundings.


-They eat mainly seeds includes corn, oats, cherry, along with small amounts of knotweed, elm, poison ivy, and barley.

-In cities, feral pigeons also eat popcorn, cake, peanuts, and bread

Columba livia(Rock Dove and Common Pigeon)

Campylorhynchus brunneicapillus cactus wren


The Cactus Wren is common throughout the southwestern United States.

This arid desert, dominated by cholla and other succulent cacti and spiny trees and shrubs, is characterized by high temperatures, low humidity, and scarce water.


The Cactus Wren primarily eats insects, including ants, beetles, grasshoppers, and wasps.

Occasionally, it will take seeds and fruits.

Almost all water is obtained from food, and free standing water is rarely used even when found

Campylorhynchus brunneicapillus(Cactus Wren)

Callipepla gambelii gambel s quail


Gambel's Quail live in warm deserts with brushy and thorny vegetation

These birds also survive well in cultivated communities and prefer mesquite lined river valleys and drainages near these lands

Common plants found in the quails' habitat include: desert hackberry, mesquites, little leaf sumac, desert thorns, catclaw acacia, scrub oak, and various other types of desert shrubbery


Ninety percent of the Gambel's Quail diet comes from plants.

Various types of seeds and leaves are eaten throughout the year.

During certain times of year fruits and berries from cacti are eaten.

A few insects are eaten during the nesting season in spring and early summer.

Callipepla gambelii(Gambel's Quail)

Zenaida macroura mourning dove


Mourning doves like farms, small towns, open wood, scrub, roadsides and grasslands.


Mourning doves eat a wide variety of seeds, waste grain, fruit and insects.

Occasionally, they eat in trees and bushes when the ground foods have become scarce.

Doves also like to ingest agricultural crops. Those especially coveted are cereal grains such as corn, millet, rye, barley, and oats.

On rare occassions, doves can also be seen preying on grasshoppers, ants, beetles, and snails.

Zenaida macroura(Mourning Dove)

Passer domesticus house sparrow


House Sparrows like areas that have been modified by humans, including farms, residential, and urban areas. They are absent from uninhabited woodlands, deserts, forests, and grasslands.


House Sparrows forage on the ground, eating a variety of seeds and grains, sometimes obtained from livestock feed or livestock droppings. They also eat insects, spiders, and fruits in the summer.

Passer domesticus(House Sparrow)

Road runner


desert scrub, chaparral, arid open woodland, brush


consists mostly of animals (insects, reptiles, rodents, birds, etc.), but will occasionally eat fruit (mostly from cactus) and seeds.

Road Runner

Data collected

U of A

Sparrow – 81

Pigeon – 19

Catalina Mountains

Mourning Dove – 48

Sparrow – 12

Cactus Wren – 7

Quail – 27

Road Runner – 2

Pigeon – 4

Data Collected

Calculations using inference on proportions for two independent samples z test

State Hypothesis

Ho : p1 = p2

Ha : p1 > p2

Find Test Statistic- Z

x = number of species counted

n = total birds counted in habitat

Z = 1.95

Find P Value

P = P(Z > z)

P = P(Z > 1.95)

= 0.0256

State Conclusion

We reject our null hypothesis. We have reason to believe that more Mourning Doves habitat the Catalina Mountains versus the University of Arizona campus.

This can be concluded since our P-Value is smaller than our significance level of 0.05.

Calculations: Using Inference on Proportions for Two Independent Samples Z-test

Calculations using shannon diversity index
Calculations: Using Shannon Diversity Index

*The Shannon Diversity Index is used to compare species diversity

between study sites.

Shannon Diversity Index equations used:

H1= (nlogn- ∑ f1log f1) / n

varH = (∑ f1log2 f1 –(∑ f1log f1)2 / n)/ n2

t = H1 – H2 / (√ var H1 + var H2 )

*t – to determine if two values you obtain for the index are

significantly different you can use the t-test

df = (varH1 + var H2 )2 / ((varH1)2 / n1 + (var H2) 2 / n2 )


Sample Calculation for Pigeons:

H1= (23log23- ∑ 19log 19) / 23 = .3054

varH1 = (∑19log2 19–(∑ 19log 19)2 / 23)/ 232 = .0102

H2= (23log23- ∑ 4log 4) / 23 = 1.257

varH2 = (∑4log2 4–(∑ 4log 4)2 / 23)/ 232 = .0022

t = .3054 – 1.257 / (√ .0102 + .0022 ) = 8.55

df=(.0102 + .0022 )2/((.0102)2/19+(.0022) 2/4 )= 23.35

t > 2.8 therefore we reject the null hypothesis


  • Due to our findings we must reject our null hypothesis.

  • We have observed that a greater number of bird species can be found outside the city, Catalina’s, than within the city, UofA.

Conclusion continued
Conclusion Continued…

  • Possible Error:

    • More than one person observing sights.

    • Counting same bird twice

  • How could the experiment be improved?

    • Focus on one species

    • Choose more locations

    • Longer observation periods and more days

    • Tag Birds


  • Our experiment has shown that humans have a definite impact on the habitation of birds.

  • This information could help save bird, and other, species from human encroachment and stop developers from pushing housing farther into the Catalina’s.


  • We used a couple websites including: