Water Habitats a Refugium for Winter Birds Along the Central Niobrara River

By James Ed. Ducey

Aquatic habitats along the central Niobrara River in Cherry county are a unique setting for winter birds. Birds typically known as summer residents in the region, also occur in winter months at groundwater-created settings. Ample and steady flows provide different micro-habitats, notably: 1) spring-flow brooks, with occasional falls, dead trees and other brook-side features; and, 2) wetlands along the river terrace that do not freeze entirely during the winter, the marsh often the result of beaver dams that retain the water; and 3) moist seep areas with a permanent water flow.

The availability of these habitats is dependent on groundwater flows from the adjacent, upland sandhill dunes. The water flows to the surface where an impermeable rock strata is exposed within the deeply excised river valley. These flows continue year-round, despite temperatures less than -20^o.

These unique settings are a residence for winter birds, notably the Virginia Rail, Wilson's Snipe, Winter Wren and Marsh Wren. Recent records for occurrence of these species provide for some northern-most records for the central Great Plains. Their winter residence is a new feature for the avian biogeography of the central Niobrara River in Nebraska.

Virginia Rail

The first record was from April 2004, along the river south of Nenzel. There was a bird at the same locale on 6 June. They were not found at this wetland terrace again until mid-October and mid-November 2004.

On 16 December they were heard both at the river terrace marshes along highway 91 south of Merriman and south of Nenzel.

During a survey for the Great Backyard Bird Count (February 2005), there were good results for paying the high price of gas to travel. This rail was at the Jim Gray Place and Circle J Reserve on 18 Feb, and on 19 February at Niobrara tract wetland at McKelvie Forest.

Possibly two birds could have been present at the Circle J wetland, with its larger, open habitat. A bird was heard within a few minutes at two spots in the marsh, perhaps just from a rambunctious rail getting around, or another resident.

These records are not a sighting of the rails. The tally is from a distinctive, and sometimes loud response to my imitated approximation which is obviously similar enough to get a rail to respond with their vocalization. Usually there is a complete phrase heard to provide a key characteristic to identify the species. At the forest service wetland, the rail was loud enough to get the ranch dog to barking across the river. Any sounds made the rails are limited, with typically few responses heard.

Rails were noted on two sites in January 2006: Niobrara Tract, McKelvie Forest, and a wetland at Mogle Falls.

These winter dates vary significantly from dates which typically range from the first week of April to mid-November, based on about 250 Sand hills records. Winter records for January and February dates are known from the Lewellen marshes west of Lake McConaughy, according to Johnsgard and Rosche, and the species winters regularly at the cattail seeps in the North Platte river valley (Ross Silcock, personal communication).

Wilson's Snipe

This bird is found at creeks or spring seeps where moist soil is still present as the temperatures get bitterly frigid.

Along the Niobrara river, my first, early season record was February 27, 2004 in an oozy spring-water place along the first-level terrace of the river south of Nenzel. A single bird was also seen at Coon Creek at Fort Niobrara NWR on 18 December 2004.

Considering sandhills records, there were two on January 2, 2003 at a flowing well at Brush Lake, once the headwaters-lake of the North Loup River. They were reported from Lake McConaughy on February 17, 1979 (Rosche and Johnsgard 1984, Birds of Lake McConaughy and the North Platte river valley, Oshkosh to Keystone).

December records are on 8 Dec 1981 at Crescent Lake NWR (refuge bird chronology records). There are multiple Jan-Feb reports from Scotts Bluff, Keith, Lincoln, and Lancaster counties, and it has been reported in midwinter as far north as Dawes, Cherry, and Antelope counties; and is generally considered an uncommon winter visitant in northwest Nebraska (Silcock, personal communication).

January 2006 sightings occurred at Buckhorn Spring, Bobcat WMA and Keller WMA.

Winter Wren

After locating this feathered mite at three Omaha parks – in association with spring flows - after idle speculations about finding this species at spring-flow places along the Niobrara.

The first sighting was during an unsuccessful search for the American Dipper. There were two Winter Wrens at Sears Falls, on Fort Niobrara NWR. Further downriver, there was one at the Conservancy Swamp, on cedar trees in the marsh along the river in northern Brown County. This species was not listed on the refuge birdlist, or the Niobrara Valley Preserve birdlist.

In central Cherry county, a bird was seen well enough to be identified south of Nenzel in mid-November 2004 at Buckhorn Spring.

During a subsequent December outing, the species was noted at three locations. On the 15 December 2004, there was one well seen on timber over the brook at the canyon north of McKelvie forest. On 18 December they were noted at Borman Bridge WMA. They were also found at Smith Falls State Park, where after working slowly along the brook from the Niobrara River, to the falls, around and to the source springs, there were no wrens found. The place was the most appealing place for the species that I had found, so it was surprising to not see them. I finished hiking the area for a survey of other birds, and decided to look around again below the falls. This was when a wren was seen, but only after the arduous task of hiking along the waters.

During the backyard bird count survey in February 2005, this wren was seen after some time at Buckhorn Spring. My route went from the ample spring, along the brook, over the falls, and to the river, and then back southward, following the west branch where the wren was flushed.

This is an interesting place for local bird geography. On the first time, my route to see a bird at the brook depths went down the west spring-branch canyon. It was realized later, upon a detailed look at maps, that this was not Buckhorn Spring, but a spring-branch canyon a quarter mile to the west. For the great American bird count, just to ensure a current record, my route included a visit to the real Buckhorn Spring - a national, geographic place name - to see a wren.

Digital elevation models for Buckhorn Spring and Borman Bridge WMA, showing the deeply incised character of the spring-branch canyons used by winter wrens. Elevations at Buckhorn spring are 2658' at the canyon bottom at the river level, and 2860' on the upland to the south. Prepared at nationalmap.gov.

A geographic perspective can depict the incised character of this locality. The topographic map shows the general terrain features of the spring-branch canyons used by these wren, but a digital elevation map shows the incised nature of the Buckhorn Spring sites.

The extent of this habitat feature can be considered by browsing the online maps, looking at the south side of the valley where this habitat occurs. There may be other suitable places for Winter Wrens westward in Cherry County, but similar attributes are certainly more prevalent eastward from the confluence with the Snake River. This characteristic is notable at Borman Bridge WMA, for example. There are numerous other spring-branch canyons along the scenic river section of the Niobrara River east from Borman Bridge near Valentine, down river through Keya Paha-Brown-Rock counties country. Sites with a similar setting are potential places for these wrens to occur.

This species is known to overwinter at several locales in west and northwest Nebraska, but had not been noted during the winter along the Niobrara valley. A singing bird was observed by Chris Anderson from 23 May through 13 June 2000 in the Tyler Falls area of Ft. Niobrara NWR. There was a winter wren seen at the Niobrara Valley Preserve in the autumn of 1982, according to Mark Brogie.

In January 2006, the feathered mitester was noted at numerous locations in the valley: Buckhorn Springs, Mogle Falls, Anderson Bridge WMA, Sears Fall at Fort Niobrara NWR, Broyer Canyon, Bobcat WMA and Long Pine WMA.

Marsh Wren

This wren was first noted in the wetland along on the river terrace south of Nenzel. It was located by pishing and making others sounds to elicit a response from any birds in the marsh. Birds present usually would respond. A few times they would erupt with song for a few moments.

Visits to the wetlands along the scenic Niobrara, included particular efforts to locate wrens. They were first heard on 27 Feb 2004 at the private land south of Nenzel, with repeat records on 9 and 17 March (Figure 3). My pishing got a first response south of Merriman on 24 Mar 2004.

Wrens were not noted during two June visits to the wetland south of Nenzel.

On 16 Dec 2004, they were at the Circle J Reserve (north 1/2, sec. 34, T33N R31W) and a wonderful four at the Jim Gray Place, the land-owners' designated name for the ranchland tract about the lakes on the Niobrara River south of Merriman (sections 28-29, T33N R37W). Three birds were seen at the west, tree-line wetland, and another on the east side of the highway.

For the bird count, my route followed that of previous surveys. The first site was south of Merriman. A slow stroll, with pishing of various sorts, was taken about the wetlands. An eventual response of song was elicited. The bird at another wetland spot, east of the highway, readily announced its presence when my route skirted the soggy wetland.

A response was heard to my sounds at the Circle J Reserve. An unexpected reply was also heard at the U.S. Forest Service wetland, on the extreme northern edge of McKelvie Division of the Nebraska National Forest. This wetland is along the river terrace (mostly in section 6, T32N R30W).

This wetland is drastically degraded by an invasion of volunteer cedar growth, and other trees which alter the wetland habitat. Woody groves fragment the habitat, reducing the extent of wetland useful for wintering birds.

In January 2006, single wrens were seen at Niobrara Tract, McKelvie Forest, Anderson Bridge WMA and wetland at Mogle Falls.

A sufficient ground flow is required to ensure enough warmer water to provide an area of unfrozen marsh habitat. This wren was not found where the entire surface of the water was covered with ice.

During the winter, this bird is also known to occur southward in the North Platte valley, and elsewhere in western Nebraska.

Summary

The Niobrara valley has been recognized for decades for its avian biogeography, with eastern species occurring with western species of summer birds. Unique avian features of the valley extend to winter species as well, with this documentation of four species of wintering birds establishing locales that are a refugium for winter birds. The known occurrence, plus additional points of expected occurrence, indicate another distinctly unique feature to the biogeographic aspects of the river valley.