Climate Change Effects on Animal Distribution and Evolution
INSTRUCTOR’S LABORATORY OUTLINE
Objective: Using online research databases and available classroom resources, students will examine
historical population changes related to historical weather data utilizing MS Excel spreadsheets.
Skills Gained: Accessing online databases, using MS Excel to produce interpretive graphs of online data,
interpreting research data, forming a hypothesis based on preliminary data and research literature.
I.
Introduce the rough-legged hawk (Buteo lagopus): a large Buteo (soaring hawk) similar to a
red-tailed hawk.
a. Specifically explain the annual migration pattern of red-tailed hawks (Buteo jamaicensis)
and rough-legged hawks in the northern plains. In late October, all of the red-tailed
hawks are gone, migrating to the southern U.S., Mexico, and Central America. In
December, the rough-legged hawks begin to move in. In March the rough-legged hawks
leave for their arctic nesting sites and red-tailed hawks move back in to nest in ND & SD.
The breeding range of rough-legged hawk encompasses the high arctic regions of the United States and
Canada. The rough-legged hawk breeds from western and northern Alaska, northern Yukon Territory, and
northern Labrador south to northern and southeastern MacKenzie District, central Canada, and northern
Quebec and Newfoundland. It also breeds from the Kodiak islands and Umnak north to Prince Patrick,
Victoria, Bylot, and southwestern Baffin islands (Northwest Territories).
The rough-legged hawk winters from south-central Alaska (casual) and southern Canada south to southern
California and southern Arizona, and east to southern Texas, Missouri, Tennessee, and Virginia. On the
East Coast wintering rough-legged hawks occur from Cape Cod to Chesapeake Bay and are occasionally
observed in eastern Texas and on the Gulf Coast.
--USFS (www.fs.fed.us/database/feis/animals/bird/bula/all.html)
II.
b. Have students pull-up photographs, or examine bird field guide entries, of rough-legged
hawks to review the species’ characteristics.
Introduce the Christmas Bird Count (CBC)
a. The CBC is an Audubon society program that relies on volunteers to conduct annual bird
surveys over the Christmas holiday.
From December 14, 2008 through January 5, 2009, tens of thousands of volunteers throughout the
Americas took part in an adventure that has become a family tradition among generations. Families
and students, birders and scientists, armed with binoculars, bird guides and checklists went out on
an annual mission - often before dawn. For over one hundred years, the desire to both make a
difference and to experience the beauty of nature has driven dedicated people to leave the comfort
of a warm house during the Holiday season.
Each of the citizen scientists who annually braves snow, wind, or rain, to take part in the Christmas
Bird Count makes an enormous contribution to conservation. Audubon and other organizations use
data collected in this longest-running wildlife census to assess the health of bird populations - and to
help guide conservation action. ---CBC Website
--
Have students pull-up the CBC Website (www.audubon.org/Bird/cbc/).
On the CBC Website, create a spreadsheet for the rough-legged hawk in North Dakota and
South Dakota between the years 1968 (Year 68) and 2008 (Year 108).
a. Steps:
i. On left navigation bar under Results, click on historical
ii. At the bottom click on By Species under the middle chart
iii. Type in Rough-legged Hawk in the name box and click Search
iv. Select the first entry (Rough-legged Hawk), click Add
v. Select 68 as the start date and 108 as the end date
vi. Select North Dakota and South Dakota from the region box, clicking Add for
each.
vii. Click Make a Table on the bottom right of the screen
viii. On the next screen, click download the data—this makes an Excel file of the
data.
b. Then, insert a line graph with the year (x-axis) and the number per hour (y-axis)--instructions below:
Rough-legged Hawks observed (CBC) in ND
and SD between 1968 and 2008
Birds per survey hour
III.
IV.
0.25
0.2
0.15
0.1
0.05
0
68 72 76 80 84 88 92 96 100104108
i. Select the Entire Column “Numb Per Hour” –this is the number of rough-legged
hawks observed per hour of survey.
ii. Click the Insert Tab, then select a Line Graph
iii. Right Click on the x-axis and click on Select Data—we need to change the x-axis
values.
iv. In the Horizontal (category) Axis Labels box, select edit
v. Then select the Year column data and click OK, then OK again
vi. To add the line, right click on the existing line, click Add Trendline, then Close.
vii. Edit axis and chart titles as you see fit.
c. Question: What is the general overwintering population trend of rough-legged hawks in
ND & SD between 1968 and 2008?
i. There is a general increase in the number of rough-legged hawks observed
between 1968 and 2008.
d. Question: What are some reasons for the fluctuation in annual observations?
V.
VI.
i. Various Answers, including changes in precipitation, changes in overall
population, researcher error (or different researchers), changes in prey
abundance.
Find temperature data at the Bismarck Station between the years 1968 and 2008.
a. Have students pull-up Temperature Website (www.rimfrost.no/)
i. Select USA, Select Bismarck
ii. Type in 1968 as start and 2008 as end
iii. Select Stat-Month in drop down
iv. Select Graph Years & Trend in drop down
b. Question: What is the general trend in temperature between 1968 and 2008?
i. General increase in temperature between these years.
Compare the temperature graph with the rough-legged hawk observation graph.
a. Question: Does there appear to be a correlation between temperature and
overwintering rough-legged hawk populations in ND & SD?
i. Yes, there is a positive correlation between increasing temperatures and the
number of overwintering rough-legged hawks observed in ND & SD
Discussion Questions
1. List several sources of “bias” that a researcher should understand when using CBC data.
Although there are some concerns with the CBC data, these long-term, landscape-or-larger
scale databases provide some of the best current data concerning climate change effects on
animal populations.
2. Research the diet of Rough-legged Hawks and provide a hypothesis for the trends in
overwintering populations that you observed in this lab. A correlation between snow depth
and the number of rough-legged hawks in this area was illustrated by comparing studies
during a low snowfall year—2006/07 (Jones, Ducheneaux, and Guinn) and a high snowfall
year—2008/09 (Luger, Halsey, and Guinn). Rough-legged hawks have small feet and catch
mainly mice and voles—deeper snow makes it nearly impossible for them to find their prey.
3. Recently, a hybrid Bald Eagle x Stellar’s Sea Eagle was observed for the first time (Clark
2008). Stellar’s Sea Eagles are a Russian and Asian species that is becoming more common
in northern Alaska because of climate change. What impact would a larger, more aggressive
eagle hybrid have on the Bald Eagle population? What impact would this hybrid have on
Indigenous people who revere Bald and Golden Eagles?
Currently in ND & SD red-tailed hawks and rough-legged hawks do not occur in the same
area at the same time. However, continuing changes to the distributional patterns of these
species may result in increased competition for limited winter resources. Alternatively, if
climate change expands changes to distributions of these species in the spring, hybridization
may result. The consequences of hybrid Buteos in the community are unknown.