A Look at Populations of Grassland Birds and Vegetation Within the Reclaimed Mine Area The Wilds

Muskingum Fellowship Research ReportAllie Leggatt, Connor Hann, Jennifer Hastings, and Sarah Landuyt

Introduction

Due to habitat loss, grassland bird populations are in steep decline. For example, due

habitat encroachment, only 4 % of the original tall grass prairie land in the Midwest area (1994)

is left which in turn has been a major factor in the species’ decline. However, recently grassland

birds have utilized reclaimed mine areas for habitat and nesting.(Jaster et. al. 2014). Thus the

focus of this study is on grassland bird populations at a reclaimed surface mining area in

southeast Ohio known as The Wilds. The focus species observed and recorded were Henslow’s

Sparrows (Ammodramus henslowii), Grasshopper Sparrows (A. Savannarum), Bobolinks

(Dolichonyx oryzivorus), Eastern Meadowlarks (Sturnella magna), and Savannah Sparrows

(Passerculus sandwhichensis). Data collection was conducted through a point count method

(discussed in methodology) over span of the three months of May, June, and July. More

extensive work was also conducted specifically on finding the rare, elusive Henslow’s sparrows’

territories, as Henslow’s are known to breed in restored grasslands (Jaster et. al. 2013). Along

with the data collection of population abundance of the focus birds, vegetation analysis was done

to have a further understanding of the birds preferred habitats and the condition of the reclaimed

grassland. This vegetation data collection focused on areas where our bird point counts were

conducted. This study’s data, results in a clear picture of the present abundance of grassland

birds and vegetation at The Wilds, but also is planned to be used in the future to hopefully

determine the rise or further decline of grassland birds in North America.

Methods

The bird point counts were conducted throughout the summer months of the 2014

breeding season at the Wilds, Ohio. In order to conduct the bird point counts, 40 points were

placed in the Southern Sector (International Road) and the Zion Ridge Sector (Zion Road) in

previous years to the 2014 breeding season. The points were marked with wooden stakes that had

flags taped to the top of the stakes as well as flags placed in the surrounding area. Ribbons were

also tied around the stakes making them easier to be located. In the Southern Sector, the stakes

were created by a computer mapping program and numbered 1 through 23. Each point was 200

meters away from the next point. In the Zion Ridge Sector, the points were placed alongside the

road 200 meters from each other. Each point had a number written on the stake and flags. Next,

the GPS coordinates were taken at each point. The point counts were conducted once a month in

May, June, and July. The study is a continuation of research done previous years and the

protocol for conducting a bird point count is a modified version of the Breeding Bird Survey

technique.

2014 Grassland Focus Area Point Count Survey Protocol: The objective of this study is to

complete avian surveys among grassland and shrubland habitat at the Wilds. The purpose of this

study is to sample bird populations for estimated densities of grassland dependent species;

determine longitudinal trends in populations for specific regions; assess habitat preferences; and

provide future recommendations for habitat management. Priority species at the Wilds included

bobolink, dickcissel, eastern meadowlark, field sparrow, grasshopper sparrow, Henslow’s

sparrow, northern harrier, northern bobwhite quail, prairie warbler, ring-necked pheasant,

savannah sparrow, short-eared owl, sedge wren, vesper sparrow, willow flycatcher, yellow-

breasted chat, and upland sandpiper. Other species that were not considered priority species were

observed at the Wilds. These species included indigo bunting, common yellowthroat, yellow

warbler, American goldfinch, song sparrow, European starling, northern flicker, American robin,

northern cardinal, red-winged blackbird, Baltimore oriole, orchard oriole, chipping sparrow,

house sparrow, house wren, Carolina wren, horned lark, killdeer, etc.

The point counts were conducted by doing a 6 minute count at each point. Once arriving

at the point the researchers waiting approximately 1 minute to let the surrounding birds settle

back after the disturbance the researchers may have caused by walking through the habitat to get

to the point. While waiting for the birds to settle, the data collector recorded the date, time,

temperature, wind speed, location and names of the researchers. After the minute was up the

survey began and the individuals identified all of the birds seen and/or heard within the 100

meter radius of the circle. The researchers recorded the direction of the bird and the distance it

was from the point by using a distance range finder device. If the sex of the bird could be

identified, it was also recorded on the sheet. Birds that were out of the circle’s radius were

marked as “out” to recognize that they were there, but could not be used in the data entry portion

of the research. If the bird flew over the circle but did not land in the circle, it was recorded in

the field as a “fly over” but excluded from the final data sheet. The species were identified on the

data sheet by codes that made it simple and time efficient to write what species were being

observed. If the individual only heard the bird, then the code was circled. The code was not

circled if the individuals only had visual contact or had auditory and visual contact of the bird.

During the month of June, a vegetation analysis was conducted. This was only done once

at each of the 40 points at the Wilds. Each point was known as the “home point”. From the home

point a 5 meter radius was created by setting flags at the North, South, East, and West directions.

At each of the directions a measurement of the litter, live vegetation and dead vegetation was

taken. Within the circle a percent was given to the litter, live vegetation, dead vegetation, woody

over a meter, woody under a meter, forbes, and grasses so that the individual percentages added

up to 100 percent. From the home point three more circles were conducted the same way. The

first circle was 30 meters at 240 degrees from the home point. The second circle was 60 meters

at 120 degrees and the third circle was 90 meters at 0 degrees. By adding three extra circles to

each home point, the researchers were able to get more data that represented a better depiction of

the surrounding habitat and what that habitats structure was.

Results

Average Number of Birds Counted Per Point at Zion Ridge

May June July0

0.2

0.4

0.6

0.8

1

1.2

1.4

Henslow's Sparrow

Grasshopper Sparrow

Red-Winged Blackbird

Month of data collection

Aver

age

num

ber o

f bird

s at e

ach

poin

t

Average Number of Birds Counted Per Point at the Southern Sector

May June July0

0.5

1

1.5

2

2.5

3

Henslow's SparrowGrasshopper SparrowRed-winged Blackbird

Month of Data Collection

Aver

age

num

ber o

f bird

s at e

ach

poin

t

19.5

18.5

11.510.6

8.8

6.4

5.3

4.4

4.4

3.53.5

1.8 0.9 0.9

Average Percentage of Birds at Zion Ridge for May

Red-winged Blackbird

Grasshopper Sparrow

Henslow's Sparrow

Yellow Throat

Bobolink

Meadowlark

Willow Flycatcher

Yellow Warbler

Field Sparrow

Robin

Song Sparrow

Killdeer

Goldfinch

Eastern Towhee

30.7

26.8

10.2

7.3

6.3

4.8

3.9

22

1.5 11 1 1

0.5

Average Percentage of Birds at the Southern Sector for May

Redwinged Blackbird

Bobolink

Meadowlark

Song Sparrow

Yellow Throat

Henslow's Sparrow

Willow Flycatcher

Yellow Warbler

Robin

Field Sparrow

Grasshopper Sparrpw

Goldfinch

Killdeer

Woodcock

Catbird

20 30 40 50 60 70 80 90 100 1100

1

2

3

4

5

6

Correlation between Henslow's Sparrow and Vegetation

Series2Linear (Series2)

Average vegetation Height (in centemeters)

Num

ber o

f Hen

low

's Sp

arro

ws p

er p

oint

Fescue Blue Grass Brome0

5

10

15

20

25

17.2

13.1 12.7

2.6

23

16.5

Average Percentage of Three Main Grasses Surveyed

Zion RidgeSouthern Sector

Vegetation Type

Aver

age

Perc

enta

ge

17.2

13.1

12.7

11.7

9.6

8.9

8.3

6.3

4.63.3

2.21.1

1

Average Percentage of Vegetation at Zion Ridge

Fescue

Blue Grass

Brome

Bird's Foot

Yellow Sweet Clover

Other Forbes

Litter

Lespedeza

Dead Vegetaion

Other Grasses

Bare Ground

Woody >1

Woody <1

23

19.6

18.3

16.5

7

53.1

2.6

1.9 1.2 1.2 0.4 0.2

Average Percentage of Vegetation at the Southern Sector

Blue GrassOther ForbsBird's FootBromeLitterOther GrassesDead VegetationFescueBare Ground

LespedezaWoody >1Woody <1Yellow Sweet Clover

Discussion

From the data collected, it was observed that there are varying concentrations of different

species per sector studied (Southern and Zion Ridge Rd.). The species focused on in this report

are the Henslow’s Sparrows, Grasshopper Sparrows, and Red-Winged Blackbirds. These varying

concentrations could possibly be attributed to a few factors; one being that some species are

“area-specific”, meaning these species prefer a more specific habitat than what The Wilds

generally consists of. Therefore, these birds are not as heavily prevalent as others unless the

research is being done near or within their preferred terrain. Terrain can differentiate primarily

through vegetation. Different abundances of plant species, depth of field litter, height of

vegetation, and the amount of dead and woody vegetation all contributes to the condition of an

area and therefore alters the species of birds inhabiting it.

The abundance of the types of vegetation varied from the southern sector to Zion Ridge.

In the southern sector the most abundant type of vegetation was blue grass with an average

percentage of 23. At Zion Ridge the most abundant type of vegetation was fescue with an

average percentage of 17.2. Some other major vegetation differences between the two sectors

were with the percentages of other forbes and yellow sweet clover. In the southern sector, other

forbes was the second most common vegetation with an average percentage of 19.6. At Zion

Ridge other forbes only consisted of a 8.9 average percentage of the vegetation. At Zion Ridge

there was an average percentage of 9.6 yellow sweet clover whereas in the southern sector there

was only an average percentage of 0.2. Three main types of grasses- fescue, brome, and blue

grass- were observed during the vegetation analysis. In the Zion Ridge area the average

percentages of the grasses were fescue at 17.2, blue grass at 13.1 and brome at 12.7. These

results were quite different from the southern sector where blue grass had an average percentage

of 23, brome had an average percentage of 16.5, and fescue only had an average percentage of

2.6. This shows that there is a lack of fescue in the southern sector but an abundance of it at Zion

Ridge.

There are many potential reasons why there is a variance in vegetation between the

southern sector and the Zion Ridge area. There are two different types of vegetation, warm and

cold, at the two sections. Warm vegetation areas have been planted whereas cold vegetation

areas have been allowed to grow naturally. Both sectors have four warm section points so the

variance probably lies in what has grown naturally in both areas. A possibility is the two areas

may have begun to regrow at different times. Also, the points at Zion Ridge lie alongside a road

whereas the points in the southern sector are away from the road. Car exhaust and potential

differences in the soil could possibly cause differences in the vegetation makeup. Differences in

wind, weather, and animals may also have contributed to the spread or destruction of certain

vegetation types in the two areas. Although not much is known about why the differences occur,

it is clear to see that there are several differences in the average percentages between Zion Ridge

and the southern sector.

At the Zion Ridge Rd locations, on average there were 0.77 Henslow’s sparrows in May,

0.71 in June as well as July. For the Southern Sector, there were 0.39 Henslow’s sparrows in

May, 1.48 in June, and 1.65 in July. For the Zion Ridge locations, the number of Henslow’s

sparrows remained fairly consistent while the number of sparrows at the Southern Sector

dramatically increased as the summer continued. This may be attributed to the fact that

Henslow’s sparrows prefer larger grasslands (more characteristic of the Southern Sector), and

therefore breeding activity is expected to be greater there.

When observing Grasshopper sparrows, that there was a fair amount more of these birds

found at the Zion Ridge locations as opposed to the Southern Sector locations. In May, there

were 1.24 birds per point, 0.94 in June, and 0.59 in July for the Zion Ridge points. Contrary to

that, at the Southern Sector there were 0.087 birds per point in May, 0.043 in June, and 0.174 in

July. Numbers decreased at the Zion Ridge locations, but rose and fell at the Southern Sector

locations. This may be attributed to less breeding activity at the Zion Ridge Road sector.

After analyzing the data collected on the Red-Winged Blackbirds, it was noticed that at

the Zion Ridge section, numbers stayed very consistent at 1.29 birds per point for May, June, and

July. At the Southern Sector, numbers decreased, starting at 2.73 in May, 2.39 in June, and a

mere 0.609 in July. This could be due the different vegetation and terrain or the nesting success

differing between the two sectors.

Conclusion

This research has established that grassland bird populations have found The Wilds as

suitable grassland to inhabit, specifically for nesting; however the vegetation and month does

have effect on population abundance. Although this research has concluded, this data will be

compiled with previous research at The Wilds, including ones that have been conducted by the

Ohio Division of Wildlife. More data is needed to gather a strong correlation between grassland

birds and reclaimed grasslands along with a realistic estimate of grassland bird populations.

Another interesting aspect of reclaimed grasslands, including with The Wilds, is woody

vegetation encroachment and its effect on grassland bird breeding (Ingold et.al 2013). The

research clearly establishes that woody vegetation has an effect on bird populations; however as

more woody vegetation encroachment continues its long term effects should be observed. It is

important to always consider some error in research; however in future research some of this

error can be reduced. A longer “resting time” of 5 minutes, allowing the birds to settle back

down more, before conducting the point counts would give a more realistic idea of the

amount/type of birds in the area without human interference. The suggestion of doing line

transact data collection between points was also made in the month of July, however it was too

late in research to get conclusive data. The line transacts method would give a more accurate

overall population of birds, specifically Henslow’s sparrows, than the point count method which

might have concentrated populations. A better system could also be created to avoid counting the

same bird multiple times or counting in “fly –ins”. With these suggestions and reduction in errors

in future grassland bird research, more knowledge can be gained about grassland bird

populations.

References:

Ingold, D. J., & Dooley, J.L.(2013). Nesting Success of Grassland and Shrub-Nesting Birds on

the Wilds, an Ohio Reclaimed Surface Mine. Ohio Journal Of Science, 111(2-5) 37-41.

Jaster, L., Jenson, W., & Forbes, A. (n.d). Abundance, territory sizes, and pairing success of

male Henslow’s Sparrows in restored warm-and cool-season grasslands. Journal Of

Field Ornithology, 84(3), 234-241.

Jaster, L., Jensen, W. E.,& Forbes, A.R.(2014). Nest Survival of Grassland Birds in Warm-and-

Cool season Grassland Restorations. American Midland Naturalist, 171(2), 246-25.