Marbled Godwit

A regular breeding resident and migrant; the Marbled Godwit was an uncommon species during the Minnesota Breeding Bird Atlas (MNBBA).

Marbled Godwits have a fairly restricted breeding range, limited largely to the northern Prairie Pothole Region of the Great Plains and Prairie Provinces of Canada. Two very small, isolated breeding populations occur along the south end of James Bay, in Ontario and Quebec, and on the Alaskan peninsula. Breeding populations reach their highest densities in southeastern Alberta (Figure 1).

Ranked as a species of High Concern by the U.S. Shorebird Conservation Plan Partnership and assigned a Continental Concern Score of 14/20 by Partners in Flight. Officially listed as a Special Concern Species in Minnesota; designated a Species in Greatest Conservation Need by the Minnesota Department of Natural Resources.

Short- to long-distance migrant wintering primarily along the coasts of southern California and Mexico.

Primarily aquatic invertebrates secured by probing.

Shallow nest depression on the ground lined with grasses.

When Roberts wrote his treatise on Minnesota birds in 1932, the Marbled Godwit had already suffered a significant decline in population numbers and a contraction of its breeding range. “Fifty years ago” he wrote, “it was an abundant summer resident throughout all the prairie region and still earlier it undoubtedly nested to some extent in more open areas in the southeastern part of the state.” Evidence that they nested widely includes Hatch’s report in 1892 of godwits occasionally nesting as far east as the “vicinity of Minneapolis” (Hatch 1892) and an 1871 report of confirmed nesting approximately 50 miles northwest of St. Paul (Roberts 1932). Confirmed nesting accounts (nests with eggs or recently hatched young) with more detailed location information were limited to Grant, Hennepin, Otter Tail, Polk, and Stearns Counties. Despite Roberts’s assertion that the species was present throughout Minnesota’s prairie region, Green and Janssen (1975) later noted there were no early records south of the Minnesota River.

Their sheer abundance in the late 19th century was well illustrated by an account of a visit Roberts and a colleague took to Grant and Traverse Counties in 1879. The Marbled Godwit “was so abundant,” he wrote, “so constant and insistent in its attentions to the traveler on the prairies, and so noisy that it became at times an actual nuisance.” It was during the late 19th century when scores of godwits were shot. The stately bird was an easy target for the sportsman and “a plump and toothsome morsel for the table” (Bent 1927). This hunting pressure coupled with the extensive loss of Minnesota’s western grasslands and wetlands resulted in the permanent loss of the species in portions of its range and a significant decline in overall numbers. By the early 20th century the Marbled godwit was limited to portions of west-central Minnesota and the far northwestern Red River valley. Numbers had declined so rapidly throughout its range that Bent was prompted to write that “before many years it may join the ranks of those that are gone but not forgotten” (Bent 1927). Yet, when the Migratory Bird Treaty Act was signed in 1918 and market hunting declined, Roberts himself began to witness a slow recovery of population numbers in western Minnesota.

By the time that Green and Janssen provided an updated account of the species’ status in 1975, the Marbled Godwit was once again well established as a regular breeding resident in northwestern Minnesota, primarily from Wilkin County north to the Canadian border. There were occasional reports of birds in the central and west-central regions of the state as far east as Stearns County. At the time, however, there was only 1 confirmed nesting record in the region, in Big Stone County in 1973.

A few years later, Janssen (1987) identified 11 counties where nesting had been confirmed since 1970, stretching from northern Lac qui Parle County north to Kittson and Roseau Counties. His account also included a report of birds nesting on two state Wildlife Management Areas in Brown County in 1978; positive confirmation however, was lacking. By 1998, Hertzel and Janssen had documented 1 more county where nesting had been confirmed: McLeod, west of the Twin Cities.

When the Minnesota Biological Survey (MBS) began in 1987, the western prairies were the initial focus of survey efforts, and the Marbled Godwit was among the first of the targeted bird species. A total of 286 breeding season locations were concentrated in four primary areas: (1) the Tallgrass Aspen Parklands Province in northwestern Minnesota, (2) the prairies along the Glacial Lake Agassiz beach ridges farther south in the Red River valley, (3) the upper Minnesota River valley in Lac qui Parle and Big Stone Counties, and (4) a region of grasslands primarily concentrated in western Stearns and eastern Pope Counties (Minnesota Department of Natural Resources 2016).

The MBS conducted most of its fieldwork in western Minnesota in the 1990s. More than 20 years later, observers with the MNBBA documented 183 Marbled Godwit records in 2.6% (124/4,747) of the surveyed atlas blocks and in 2.5% (58/2,337) of the priority blocks. Breeding evidence was documented in 21 blocks (Figures 2 and 3; Table 1). The birds were observed in 24 of Minnesota’s 87 counties (1 block straddled two counties: Lac qui Parle and Chippewa) and were documented nesting in 11 counties (again, 1 block straddled 2 counties: Lac qui Parle and Chippewa). Four of the counties where breeding was confirmed were new since Hertzel and Janssen (1998): Chippewa, Clearwater, Pope, and Stearns.

In the 20 years that spanned the time from when the MBS was conducted in western Minnesota and when the MNBBA was conducted statewide, the Marbled Godwit’s breeding distribution remained largely intact. There were new reports in Lake of the Woods County, which had not yet been surveyed by the MBS, and a new record in Murray County in southwestern Minnesota. Overall abundance, however, appears to have declined in the northwestern counties. The MNBBA documented only 1 record in Red Lake County, and the number of records in Pennington, Clay, and Wilkin Counties was considerably fewer than the number documented by the MBS. This pattern of decline is similar to one that has been noted for other western prairie species over the same time period. The continued loss of grassland and wetland habitats, in part driven by high commodity prices in the first decade of the 21st century, is likely responsible for these observed changes. Farther east, the small population of godwits that persists in western Stearns and eastern Pope Counties is dependent on a local grazing and dairy industry whose gradual decline is responsible for declining godwit numbers in this region as well (Russell, pers. comm; Russell et al. 2016).

Historically, the Marbled Godwit’s breeding range stretched as far south as Iowa and Nebraska and as far east as Wisconsin (Gratto-Trevor 2000). Today, however, Minnesota is the eastern boundary of its distribution. Populations are gone from Wisconsin, Nebraska, and Iowa. To the west, in South Dakota, the state’s second breeding bird atlas actually recorded an increase in the number of blocks where godwits were detected (33%) compared with the number of blocks with detections during the first atlas (24%) (Drilling et al. 2016).

*Note that the definition of confirmed nesting of a species is different for Breeding Bird Atlas projects, including the definition used by the Minnesota Breeding Bird Atlas, compared with a more restrictive definition used by the Minnesota Ornithologists’ Union. For details see the Data Methods Section.

A grassland obligate, the Marbled Godwit depends on large tracts of native grassland embedded with shallow wetland complexes (Figure 4). Generally, landscapes where godwits are present are relatively level and harbor few trees (Granfors 2009). Although they will nest in cultivated fields and pastures, they prefer native prairie. The height of the vegetation is an important feature; the birds avoid tall grasses, preferring tracts where the vegetation is less than 15 cm tall (Melcher et al. 2010). Once the young have hatched, the family moves to areas with taller vegetation (Dechant et al. [1998] 2001).

Although wetlands are important for foraging, nests are usually located at least 200 meters from the wetland edge. The godwits avoid deep, permanent wetlands with tall emergent vegetation. They prefer temporary or seasonal, shallow wetlands with short shoreline vegetation. In drought years, larger, semipermanent wetlands are used. Large tracts of land are needed to include both the upland and wetland features of the breeding territory. Indeed, Marbled Godwits rarely occur on tracts that are less than 100 ha in size (Dechant et al. [1998] 2001).

Population estimates are approximate at best. A review of North American shorebird population numbers in 2006 provided an estimate of 173,500 breeding Marbled Godwits in the Prairie Pothole Region (Morrison et al. 2006). These estimates were reviewed in 2012 in an effort to incorporate newly published reports for many species. The estimate for Marbled Godwits, however, did not change (Andres et al. 2012).

Although the Marbled Godwit remains an uncommon breeding species in Minnesota, northwestern Minnesota is a center of high abundance within its’ limited national distribution (Figure 1).  A survey conducted by the U.S. Fish and Wildlife Service several years prior to the MNBBA estimated the Minnesota population numbered approximately 400-500 breeding pairs (Russell, pers. comm.). Farther south, a field survey of Stearns and Kandiyohi Counties from 2009 to 2012 estimated the local breeding population in this region to be just 20 to 30 pairs (Russell et al. 2016).  Although a more current statewide estimate is not available, Russell (pers. comm.) now estimates that the number of pairs in Stearns County alone has declined considerably due to a loss of lands devoted to the region’s grazing and dairy industry.

Marbled Godwits reach their highest breeding densities farther west, in southern Alberta (Figure 1). In Minnesota an average of less than 1 godwit is observed per federal Breeding Bird Survey (BBS) route in the state each year. This compares to 3 in Alberta and North Dakota, and 4 in South Dakota (Sauer et al. 2017).

Since the Marbled Godwit is an upland nesting bird, the BBS is a reasonable tool for monitoring its population trend. Since 1966, the survey has documented a nonsignificant decline of 0.41% per year throughout the species’ breeding range. Recent years, however, have shown a slight increase, averaging 0.60% per year since 2005 (Figure 5). The small size of Minnesota’s population results in a projected population trend that is not as precise as it would be in areas of greater abundance. Nevertheless, the trend line is nearly identical to that observed at the national level: an overall decline of 0.41% per year from 1967 to 2015. Across the Prairie Pothole Region, the core of the species’ breeding range, population numbers have declined an average of 0.85% per year from 1966 to 2015 (Sauer et al. 2017).

Although Marbled Godwits have certainly recovered from the devastating losses they endured in the late 19th century, they have never reoccupied portions of their former breeding range that have been lost to agricultural development. Even today, habitat loss and degradation continue to be the primary factors impacting populations on their breeding grounds, on wintering grounds, and at their migratory stopovers (Gratto-Trevor 2000). Local abundance also can vary widely from year to year in response to wetland conditions.  Marbled Godwits depend on the availability of abundant seasonal wetlands early in the breeding season for feeding. Adapted to the variable precipitation patterns encountered across the Great Plains, if drought conditions reduce seasonal wetland abundance early in the season in one area, godwits will move to other more suitable sites (Russell, pers. comm.; Gratto-Trevor 2000).

Like the Upland Sandpiper, the Marbled Godwit is considered an indicator of quality grassland and wetland habitats. Indeed, the species is less likely to use pastures, hayfields, and croplands that the Upland Sandpiper often finds suitable, demonstrating a narrower tolerance in its selection of native and restored grasslands. Its association with some of the largest and highest-quality prairies remaining in the state is a clear indication of its vulnerability.

This narrow tolerance for habitat coupled with its very restricted breeding distribution prompted the U.S. Shorebird Conservation Plan Partnership (2016) to rank the Marbled Godwit a species of High Concern and to prepare a national conservation plan (Melcher et al. 2010). The species was recently assigned a relatively high Continental Concern Score of 14/20 by Partners in Flight, influenced largely by its small population size and by threats to its breeding and wintering habitat (Rosenberg et al. 2016). In Minnesota, the Marbled Godwit is officially listed as a Special Concern Species (Coffin and Pfannmuller 1988) and a Species in Greatest Conservation Need (Minnesota Department of Natural Resources 2015).

General management recommendations focus on maintaining large habitat complexes that support quality grassland habitat and a diversity of wetlands; tracts larger than 1 km² are recommended (Dechant et al. [1998] 2001). In light of the godwits’ reliance on shorter-grass prairies, burning, mowing, and grazing are all appropriate management options if sequenced properly to provide the right conditions during the nesting season. Light to moderate grazing in the spring, for example, maintains low cover for the adults to forage in during the spring but provides denser cover later in the season for chicks (Russell et al. 2016).

An important vehicle for conserving Marbled Godwits and their habitat is the Minnesota Prairie Conservation Plan (Minnesota Prairie Plan Working Group 2011). The plan’s ambitious goals to protect and restore grassland and wetland habitats throughout western Minnesota are critical to the continued survival of many species. The work is being implemented through a consortium of state, federal, and local resource agencies and conservation organizations.

One of the important partners in this work is the U.S. Fish and Wildlife Service. Using information about sites where Marbled Godwits are known to nest in Minnesota, their Habitat and Population Evaluation Team (HAPET) in Fergus Falls developed a model to identify priority conservation areas in the state (Melcher et al. 2010; Granfors 2009). The resulting model is a tool to help resource managers focus habitat protection and restoration efforts on known breeding sites and on quality grasslands where new populations might become established.

Although loss of habitat is a primary concern for Marbled Godwit populations, warming temperatures also pose a risk for a species with such a restricted breeding range. A recent modeling analysis by the National Audubon Society predicted the species could lose 100% of its current summer range by 2080 and classified the species as “climate endangered” (Langham et al. 2015; National Audubon Society 2017). Unfortunately, the future of this impressive grassland inhabitant in Minnesota is not guaranteed, and the species warrants close monitoring.