Bird Species
Observed on Two Prairie Transects
Jeffers
Petroglyphs Historic Site
Cottonwood
County, Minnesota
June 22, 2019
Indicated singing (territorial) males of apparent nesting
species were recorded on two transects/routes at the Jeffers Petroglyphs State Historic Site, Cottonwood County, Minnesota, on June 22, 2019. Incidental observations were also made there
on June 21, 2019. Birds were recorded
while walking slowly along the Prairie Trail loops of both the North and South
loops at the site. Jeffers consists of
about 160 acres of prairie and inferences could be made about the density of
singing males per 100 acres (or hectares) from these numbers. There aren’t enough replications of the
routes to provide valid data on densities.
Instead, this information should be used as an indicator of relative
abundance or frequency on both prairie trails and for the entire site. Collection of more valid information on
densities would require a more intense technique like the Williamson
Spot-Mapping method or some similar effort.
These data can be used as a benchmark to compare future relative
frequency if a competent observer walks the trails and records the number of
singing males encountered.
I wish I could have seen this area before it was subdued by European settlers
Methods
I recorded all singing males heard or seen from any
distance along the two routes followed but attempted to record birds that I was
certain were inside the boundaries of the property. I also recorded birds flying over the
property that obviously were not nesting there (Turkey Vulture, Great Blue
Heron, Rock Dove, and both species of Swallow).
They were recorded to add to the species list for the site but should
not be considered nesting on the property.
Before arriving at Jeffers, I stopped at a small stream crossing just
south of the Sioux Quartzite quarry about 0.5 miles from the site. There I heard and saw two other species,
Black-headed Grosbeak (Pheucticus melanocephalus) and Great
Crested Flycatcher (Myiarchus crinitus) that are riparian-dependent in
this part of Minnesota. There is no
suitable habitat for them on the Jeffers site; they are included here simply
for anecdotal purposes because they are near the site.
Results
Twenty-six (26) bird species were recorded on or from the
prairie study area on June 22, 2019.
Observations were conducted from 0930 h to 1212 h under cloudy skies
with a light wind. The temperature
ranged from 63 to 68 degrees. The north
transect was covered in a clockwise pattern beginning at the main trail to the
petroglyphs then proceeding northwest, east along the north boundary then south
and southwest to the starting point. I
deviated from the transect route at one point to check some shrubs near a rock
outcrop where an obvious small amphitheater was built. The south transect was covered in a
counterclockwise pattern beginning near the display of Native American lodges, then south and southeast along the south boundary. From there I traveled northeast to near the
east boundary, then continued west to the starting point.
Native prairie evolved under a regime of fire and the prairie at Jeffers is managed with fire. Smooth brome (shown here) is one of very few invasive plants occurring in the native prairie, indicative of the success of the fire management program at the site. With luck there will be a small herd of American Bison roaming this prairie in a few years - I hope I live long enough to see them back where they are supposed to live.
Discussion
Despite the small size of the site there are two prairies
present. The “North Prairie” is made up
of robust native grasses that have long been established. The plant community
consists mainly of native prairie species that are common to remnant prairies
of southwestern Minnesota. The “South
Prairie” is a restored prairie populated with grasses and forbs that originated
from seeds obtained in Nebraska. Forbs
are not nearly as obvious (at least at this time of year) in the South Prairie
as they are in the North Prairie. This
might be an artifact of the origin of those plant species in a drier less
forb-rich environment in Nebraska.
Portions of the North Prairie benefitted from a
controlled burn in April 2019 and the robustness of the regenerating grasses
was obvious in the burned area.
Conditions were not conducive for burning the South Prairie in the
spring of 2019 and at present there is an abundance of fuel present. Given the proper wind direction, heat, and
humidity, a fire on the entire south 80 acres of the site would likely produce
a robust growth of regenerating grasses.
I was pleasantly surprised to witness so few invasive
plant species present on both prairies.
One obvious invasive, Smooth Brome (Bromus inermis) is present throughout
the site but especially along the trails leading through the prairie. Intense fires in spring and again in fall
along this trail might be beneficial in helping to control distribution and
abundance of Bromus on this site.
It is my intention to return to this prairie at least
annually to record the relative abundance of nesting species on this site. As time and funds allow, I might return at
other times of the year to record migrants.
Ideally it would be useful to re-activate my Master Bander permit and
establish a mist netting station in the grassland especially in fall migration
to obtain a better understanding of the abundance and diversity of migrant
species, especially sparrows.
And mom has done a very good job of landscaping here
Management Suggestions:
Nothing can be written by an alumnus of the Northern
Prairie Wildlife Research Center without some recommendations on managing study
areas, and Jeffers Petroglyphs is no different.
1) I highly
recommend that visitors be required to immerse the soles of their foot ware in
some type of antiseptic that will 1) remove the seeds of potential invasive
plant species or 2) kill those seeds before they can be brought onto the
prairie by unsuspecting yet well-intentioned visitors. The near-absence of invasive species (with
the obvious exception of Bromus inermis) suggests that managers at the
site are ahead of the game on keeping Jeffers relatively free of invasive
species. Sterilizing foot ware will help
enormously in this area.
2) To help educate the public, if a foot ware sterilization
effort is implemented it should be accompanied by an informational diorama or
something similar to explain why visitors are being asked to cleanse their
feet. This may be beneficial in
assisting visitors to think about what they might be carrying on their feet in
other areas.
3) The south
boundary of the site is adjacent to an active agricultural field. During my visit there I noticed several large
hay bales on the neighbor’s land indicating that the land was actively used for
producing agricultural crops. It would
be useful to establish a fire break along that south boundary to impede the
natural movement of grasses growing in the agricultural field onto the restored
prairie at the south end of Jeffers. Maintaining a similar fire break along the
east boundary of the property would help to reduce the movement of invasive
species from the adjacent agricultural pasture on that side of the
property. Lacking the necessary
equipment to establish firebreaks on those two sides of the property, I would suggest
contacting the US Fish and Wildlife Service Wetland Management District office
in Windom, Minnesota, to work out a cooperative agreement where the Service
could loan its equipment to help with the effort. The Service manages several Waterfowl Production
Areas in nearby areas of Cottonwood County, so equipment should be readily
available.
"Native" Prairie on this map shows the general location of the "North Transect". The area called "Restored Prairie" is the "South Transect" Image by Dan Bauer
4) Burn the
prairie every second or third year at a minimum.
Prairie evolved under a regime of fire and my guess is that when Native
Americans were visiting the Petroglyphs more than 1000 years ago there were
regular fires on this prairie. Perhaps
the best strategy would be to burn the south 80 acres one year and the north 80
the next, then let the prairie lie idle for two years before burning again.. Ideally, to enhance diversity of prairie plants I would burn one 80
acres in the spring and the other in the fall on an alternating schedule.
5) Contract with the Minnesota Department of Natural
Resources or a similar entity to establish plant diversity and abundance
transects on both the north and south 80-acre parcels of the Jeffers property.
These data will prove invaluable over time as an aid to assessing habitat
changes and grassland management efficacy especially under a fire management
scenario. These data could also be
coupled with future bird population census work to assess how grassland management
is affecting bird diversity and abundance.
6) Consider re-establishing Greater Prairie-Chickens on
this site. No doubt before European
settlers harnessed and subdued the prairie Greater Prairie-Chickens were the
dominant Phasianid here. Now that role
is occupied by the introduced and invasive Ring-necked Pheasant. There are several very obvious areas on the
north and south prairies where I could imagine Greater Prairie-Chickens
establishing booming grounds in the spring.
There is an abundance of agricultural land in the area that could
provide a food source for Prairie-Chickens.
There is also an abundance of agricultural land that has been set aside
in the Conservation Reserve Program (CRP) that can provide additional habitat
for Prairie-Chickens. I suggest that
management of Jeffers Petroglyphs develop a partnership with The Nature
Conservancy (which owns a number of preserves in the region) and the Minnesota
Department of Natural Resources (which has several state wildlife management
areas in the region) to cooperatively release and hopefully re-establish
Prairie-Chickens on the site.
Bobolink spends its summer in North America and our winter in the Patagonia region of Argentina, Paraguay and Brazil. During nesting season they are a conspicuous and vociferous component of the grassland bird community. This Bobolink was photographed by Dan Bauer at Jeffers on June 21, 2019
Relative
Abundance of Singing Male Birds on Two Transects
Jeffers
Petroglyphs, Cottonwood County Minnesota
(Birds present but presumed not to be nesting on the site
are highlighted in the “Notes” section)
Species
|
Number of Males on
North Prairie Transect
|
Number of Males on
South Prairie Transect
|
Notes
|
Ring-necked Pheasant
|
4
|
3
|
|
Rock Dove
|
|
3
|
Fly over
|
Mourning Dove
|
|
1
|
|
Killdeer
|
|
1
|
|
Great Blue Heron
|
|
1
|
Fly over
|
Turkey Vulture
|
|
|
Flyover on June 21
|
Eastern Kingbird
|
|
1
|
|
Bank Swallow
|
1
|
1
|
Flyover
|
Barn Swallow
|
6
|
|
Flyover
|
House Wren
|
|
1
|
|
Eastern Bluebird
|
1
|
|
|
American Robin
|
|
1
|
|
Brown Thrasher
|
2
|
|
|
American Goldfinch
|
4
|
1
|
|
Grasshopper Sparrow
|
6
|
9
|
|
Clay-colored Sparrow
|
1
|
3
|
|
Field Sparrow
|
1
|
|
|
LeConte’s Sparrow
|
3
|
4
|
|
Henslow’s Sparrow
|
1
|
1
|
|
Bobolink
|
3
|
6
|
|
Western Meadowlark
|
3
|
2
|
|
Brown-headed Cowbird
|
3
|
3
|
|
Common Yellowthroat
|
3
|
5
|
|
Yellow Warbler
|
1
|
|
|
Indigo Bunting
|
1
|
|
|
Dickcissel
|
25
|
26
|
|
Species
Accounts
Ring-necked Pheasant (Phasianus colchicus)
Seven crowing males were heard on the site of which two were flushed. No females were observed suggesting they were
incubating eggs or brooding hatched chicks. Although an invasive species,
Ring-necked Pheasant is a popular game bird for hunters and will never be
eliminated from the landscape as long as hunting licenses can be sold. In prairie regions this species generally
spends the winter in wetland vegetation.
There being no wetlands on the property I would be interested in
learning where this species spends the winter.
Rock Dove (Columba livia) Three birds flew
over me as a I walked the south transect.
Several nearby farmsteads were the likely roosting and nesting areas for
this invasive species.
Mourning Dove (Zenaida macroura) One
singing male was heard and seen on the fence along the southeast boundary of
the property. Mourning dove is known to
nest on the ground in areas where trees and shrubs are lacking. In all likelihood this bird nested in a
nearby wooded area on an adjacent property and was occupying Jeffers as part of
its territory.
Killdeer (Charadrius vociferous) A single,
vociferous, Killdeer was flushed from prairie grasses along the south
transect. Another Killdeer, likely the
same bird, was seen later that day on the exposed rocks of the petroglyphs.
Great Blue Heron (Ardea herodias) Single
birds (the same bird?) were seen flying over Jeffers on June 21 and again on
June 22. Both were flying in a northerly
direction. There being absolutely no suitable nesting or foraging habitat for
this species on the property these were incidental observation and should not
be used to suggest this is a regular part of the avifauna of the site.
Turkey Vulture (Cathartes aura) See comment
above for Great Blue Heron.
[Great Crested Flycatcher (Myiarchus crinitus)
This species was NOT on the Jeffers property but instead in a riparian area
along a stream about 0.5 miles south of the site. I include it here simply for anecdotal
purposes because of its proximity to the site.
It should not be considered a component of the Jeffers avifauna.]
Eastern Kingbird (Tyrannus tyrannus) One highly-agitated
male Eastern Kingbird was heard and seen along the eastern boundary fence of
the property. The presence of several
shrubby trees there likely provided a platform for nests but I did not take the
time to investigate.
Bank Swallow (Riparia riparia) Single Bank
Swallows were observed foraging with Barn Swallows as both species flew over
the north transect and a single Bank Swallow was observed foraging over the
south transect. Road cuts exist in the
area that could provide nesting habitat for this species but not so on the
Jeffers property. Instead this species
and Barn Swallow use Jeffers as foraging habitat and should therefore be
counted as part of the avifauna.
Barn Swallow (Hirundo rustica) Six Barn
Swallows were observed foraging over the north transect. Suitable nesting habitat platforms exist in
the area including the visitor center building for the Jeffers
Petroglyphs.
House Wren (Troglodytes aedon) One singing
male was heard in the woody vegetation along the boundary fence on the east
side edge of the property.
Eastern Bluebird (Sialia sialis) One male
was heard and then seen singing from the roof of a bluebird house established
near the north transect trail. Given the
time of year and the presence of territorial singing I assumed there was a
female with eggs or young in the nest box but did not open it to investigate.
American Robin (Turdus migratorius) An
agitated male was heard doing its “clucking” call note from the fence line at
the east edge of the property. Most likely this species was nesting in a wooded
draw east of the boundary fence and used the fence for a song perch at the
boundary of its territory.
Brown Thrasher (Toxostoma rufum) Two adults
were observed along the north transect; one was flushed from the prairie
vegetation and the other flew in to be with it.
This species commonly nests in brushy areas and as growths of Western
Snowberry (Symphoricarpus occidentalis) become established on the
prairie it is more likely that Brown Thrasher will be found nesting on the
Jeffers property.
American Goldfinch (Spinus tristis) Four
males were recorded along the north transect and a single male on the south
transect. American Goldfinch is
primarily associated with woody vegetation for nesting habitat so I doubt they
were nesting on the Jeffers property.
They are well known for feeding the seeds of thistles to their newly
hatched young, so more likely they were using the property as foraging habitat
to feed young in nests in nearby woody vegetation.
Grasshopper Sparrow (Ammodramus savanarum)
An indicator of lightly grazed or moderately grazed native prairie, Grasshopper
Sparrow occurred in numbers expected for the vegetation present. Fifteen (15) singing males on 160 acres of
prairie averaged about 9.3 pairs per hundred acres (a formerly common way of
expressing density).
Clay-colored Sparrow (Spizella pallida) An
obligate prairie species, Clay-colored Sparrow is found most commonly in and
near growths of Symphoricarpus occidentalis. In North Dakota they occur as a nesting
species in very large numbers in Western Snowberry-dominated prairie. I
recorded one singing male on the north transect where Symphoricarpus is
scarce. Three singing males (including
one that was highly responsive to a playback of its voice) were found on the
south transect where Symphoricarpus is more common. Symphoricarpus is not easily controlled by
regular burning and can expand in area if burned too frequently. About the only way of controlling it is to
develop extremely hot fires. Care should
be taken during controlled burns of the Jeffers property to avoid burning
Symphoricarpus to reduce the likelihood of its expansion across the
grassland. Allowing it to expand will
help the Clay-colored Sparrow numbers but could also lead to a reduction in the
variety of native plant species present.
Field Sparrow (Spizella pusilla) This is a
species of retired fields that have been invaded by moderate growths of woody
vegetation. The single bird I heard singing was near a growth of chokecherry (I
think) near the northwest corner of the Jeffers property. This was adequate habitat for Field Sparrow
nesting although I did not find a nest.
LeConte’s Sparrow (Ammospiza leconteii)
This is one of the most characteristic species of wet “swales” in native
grasslands. They are highly secretive and their voice is among the most
difficult to hear of any North American bird.
It sounds like its saying “Chick – eeeeeezee” and rarely sings from an
exposed perch making them difficult to detect.
Their song is in the range of 10,000 cycles per minute and most humans
hear in the 8,000 or 9,000 cycle range. I heard or saw three singing males on
the north transect and four singing males on the south transect. This is an exceptional number of LeConte’s
Sparrows for an upland prairie (more are likely to be found in sedge-dominated
palustrine emergent wetlands and other “low” prairie). Each singing male I observed at Jeffers was
found in low wet prairie vegetation.
Although well within the migration route of this species, the singing
males at Jeffers are at the southern limit of their usual nesting range. Surveys should be conducted to determine if
LeConte’s Sparrow is present in similar habitats in adjacent areas. They are well-known for having occupied
Conservation Reserve Program lands that were protected from agriculture in
North Dakota and South Dakota. Given the
abundance of CRP land in Cottonwood and adjacent counties of Minnesota, there might
be an outlier nesting population of LeConte’s Sparrow that had not been
discovered previously. The presence or
absence of this unique species should be considered an indicator of habitat
quality at Jeffers.
Henslow’s Sparrow (Centronyx henslowii) A
characteristic species of rank growths of ungrazed or lightly grazed prairie,
the presence of Henslow’s Sparrow at Jeffers indicates a species near the
northern limit of its nesting range.
Single singing males were found on both the north and the south transects. Given the difficulty of detecting this
species coupled with even mild wind, there likely were more Henslow’s Sparrows
present than the two I encountered.
Like LeConte’s Sparrow, this species has an extremely
high-frequency voice and is quite difficult to hear. Its voice sounds like its saying “sllllick”
and is usually produced from inside grassland vegetation rather than from an
exposed perch. Curiously I have found
them much more commonly in winter in places like wire grass openings in pine
forests in the Panhandle of Florida than I have throughout their nesting range.
This is another species that should be considered an indicator of habitat
quality at Jeffers.
Bobolink (Dolichonyz oryzivorus) A species
obligate to grasslands and hay fields, Bobolink has been historically difficult
to accurately map using conventional nesting species mapping methods. The three males recorded on the north
transect and six on the south transect should be considered minimums. Also, because June 22 is near the end of the
nesting cycle for this species there may be some males that have already ceased
to display or defend a territory. Rarely
have I found a singing male Bobolink in any of the prairie states after July 1
and never have I found them singing after July 5. There were twice as many singing males on the
south transect as on the north which may be a reflection of the species
diversity of prairie plants on the south transect where there were more low
“swale” areas than on the drier upland of the north transect. Data on plant species abundance on the two
transects would be useful in understanding differences in the apparent
abundance of Bobolinks at Jeffers.
Western Meadowlark (Sturnella neglecta)
Three singing males were heard and seen on the north transect and two on the
south transect. This formerly abundant
grassland species, indicative of the western prairie, has suffered sharp
population declines in the last twenty-five years. I think much of the change in population can
be related to the extensive conversion of native grassland and idle fields to
corn and soybean production as the nation has strived to increase its biofuel
capacity. During three days of traveling
in southwestern Minnesota, I saw or heard five Western Meadowlarks. All five of
them were on Jeffers Petroglyphs – I did not see another Western Meadowlark
anywhere else. It’s a sad commentary on
the status of the human environment when a species as common as Western
Meadowlark once was, is now the exception rather than the rule.
Brown-headed Cowbird (Molothrus ater) Three
males of this well-known nest parasite were found on the north transect and
three more on the south transect.
Common Yellowthroat (Geothlypis trichas) A
characteristic species of wet swales in native prairie I recorded three males
on the north transect and five on the south transect. This distribution seems to mirror the
habitats with more wet prairie areas on the south transect and fewer on the
drier north side.
Yellow Warbler (Setophaga petechia) A
single singing male on the north transect was rather surprising because of the
paucity of suitable Yellow Warbler habitat.
I would have expected this species more commonly in the wetter prairie
of the south transect but found none there.
Perhaps this was an artifact of the nesting cycle of this species (near
the end of it) rather than indicative of low numbers.
Indigo Bunting (Passerina cyanea) A singing
male was heard and seen on the barbed wire fence along the north border of the
property. Other than the chokecherry
growth in the northwest corner of the property or the woody vegetation along
the eastern border there really is no suitable nesting habitat for this species
at Jeffers. It’s a part of the avifauna
of the site but should not be considered a nesting species at this time.
[Black-headed Grosbeak (Pheucticus
melanocephalus) As I approached the Jeffers site on June 22, 2019, I heard
a Black-headed Grosbeak singing from riparian forest along a small stream about
0.5 miles south of the Jeffers entrance.
I stopped my vehicle on the bridge and listened to and watched this bird
for about 10 minutes before continuing on to the site. Its presence in this list should not be
construed as indicating that Black-headed Grosbeak is a part of the Jeffers
avifauna. It is not. This species is
included here because of its presence near the site and because it is generally
rare in any part of western Minnesota.]
Dickcissel is by far the most numerous nesting species at Jeffers. My major professor once described their voice as saying "Dick-sis-cha-cha-cha." There are other variations but Steve's interpretation is the most accurate. This vociferous Dickcissesl was photographed at Jeffers by Dan Bauer on June 21, 2019
Dickcissel (Spiza americana) Fifty-one (51)
singing males were heard and seen on the two transects; 25 on the north
transect and 26 on the south. Far and
away this makes Dickcissel the most abundant breeding bird at the Jeffers
Petroglyphs Historic Site. I found this
species in other areas near Jeffers but not nearly in the abundance I found
them on the site. Most likely that was
an indication of habitat presence, abundance and quality at Jeffers compared to
remnant patches of grassland elsewhere.
For future management of habitats at Jeffers, Dickcissel should be
considered the “Keystone” species against which changes should be compared. Its numbers should be monitored closely to
detect changes in how the species responds to management practices because it
occupies all types of prairie vegetation on the site; upland and lowland
prairie, dry and wet prairie, prairie with Western Snowberry and other shrubs
and prairie without it. The number of
indicated breeding males here is on par with or perhaps slightly higher than densities
I recorded in the early 1980s along the Platte River in Nebraska near the
epicenter of the species nesting range in the prairie biome.
