Belted Kingfisher

A regular breeding resident and migrant; regularly observed during the winter months, especially along open streams in southern and central regions of the state. The Belted Kingfisher was a common species during the Minnesota Breeding Bird Atlas (MNBBA).

Broadly distributed across Canada and Alaska south of the tree line, and throughout all but the very southern reaches of the United States. The Belted Kingfisher is sparsely distributed throughout its breeding range (Figure 1).

Assigned a Continental Concern Score of 10/20 by Partners in Flight; designated a Minnesota Species of Greatest Conservation Need by the Minnesota Department of Natural Resources.

Considered a partial migrant; birds can survive cold temperatures if open water is available. Most birds in Canada and Alaska migrate; migrants winter in the southern United States, the Caribbean, Central America, and northern South America.

A diver that feeds primarily on small fish and occasionally on other vertebrates and invertebrates.

Burrow in earthen bank.

The Belted Kingfisher is a common member of Minnesota’s avifauna. In 1932 Roberts remarked that its call, a mechanical sounding rattle, “is a common and familiar sound about the lakes and streams of Minnesota.” Even in the early 1900s, a few birds were known to stay through the winter in areas of southern Minnesota where flowing waters remained ice-free. As widespread as the species was, confirmed nesting reports (nests with eggs) were available from only three counties: Hennepin, Meeker, and Polk. Inferred nesting reports (nest holes and young fledglings) were available from Goodhue County and the Mille Lacs region.

Little had changed when Green and Janssen (1975) wrote their updated account of the species 40 years later. Janssen (1987) pointed out that it was less common in the northwestern region and delineated 13 counties, widely spread across the state, where nesting had been confirmed since 1970. Hertzel and Janssen (1998) would later identify 18 counties with confirmed nesting since 1970 (they added 6 counties to Janssen’s original list and deleted 1: Clearwater). Although the kingfisher’s breeding distribution changed little over the years, the number and distribution of wintering reports increased and included occasional observations reported as far north as the Canadian border. The majority of reports were of birds that delayed migration until waters froze over in December; reports of overwintering birds were far less common (Minnesota Ornithologists’ Union 2016).

Field biologists with the Minnesota Biological Survey have reported 290 breeding observation locations for the Belted Kingfisher. Once again these records are widely dispersed across the state, although more sparsely distributed in the northwestern counties (Minnesota Department of Natural Resources 2016).

During the MNBBA, observers reported a total of 1,462 kingfisher records in 23.6% (1,122/4,761) of the surveyed atlas blocks and in 28.7% (671/2,337) of the priority blocks. Breeding evidence was confirmed in 2.3% (110) of the blocks (Figures 2 and 3; Table 1). The species was reported in all but 1 of Minnesota’s 87 counties (Red Lake) and was confirmed nesting in 42 counties (two blocks straddled two counties, Sibley/Le Sueur and Carver/Scott); 28 of the counties were additions to the list published by Hertzel and Janssen (1998). The species was most commonly encountered in the Laurentian Mixed Forest and Eastern Broadleaf Forest ecological provinces and least common in the Red River Valley and Aspen Parklands.

As was the case with many cavity-nesting species, one of the challenges in reviewing atlas records was deciding when to accept a record for an unused nest (UN) as a valid breeding record. It was not uncommon for observers to find holes in cut banks that appeared from their size to have been excavated by kingfishers. Because cavities may remain intact for some time, the challenge was whether to ascribe their use to the five-year atlas period. The following criteria were developed for accepting an “unoccupied nest” record: (1) there were other acceptable kingfisher records in the block the same year; and (2) the record was accompanied with notes regarding the species’ presence nearby. If neither of these criteria was met, then the decision was to accept records from the last two years of the atlas (2012–2013) and invalidate those from the first three years (2009–2011) on the premise that the use of those reported early in the atlas may have predated the atlas survey period.

Overall, it appears that the breeding distribution and abundance of the Belted Kingfisher has changed little since Roberts wrote the first comprehensive account of the species in 1932. However, warmer winter temperatures have increased the number of birds that linger here each winter until waters freeze over. The same trend appears true for other states and provinces in the Upper Midwest. Although numbers have declined in most areas, the species’ widespread breeding distribution remains unchanged (e.g., Cadman et al. 2007; Chartier et al. 2013; Cutright et al. 2006; Iowa Ornithologists’ Union 2017; Rodewald 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.

The two most critical components of the Belted Kingfisher’s habitat are water bodies that support fish populations and earthen banks for nesting (Figure 4). Ideally the two are located together, such as a cut stream bank, but frequently they are separated by some distance. Field studies indicated nest sites can be 2 to 3 km away from the primary foraging area (Cornwell 1963; Mueller 2013).

The water body may be a lake, pond, stream, river, or estuary. But to provide suitable habitat, it needs to support a viable fish population and provide nonturbid waters. Water clarity is critical to enable this diving predator to sight prey as it flies or hovers overhead. Extensive beds of emergent and submerged vegetation seem to be a deterrent. At least one study (Davis 1982) suggested that stream riffles, which are an important source of prey, may be an important habitat feature.

Most nesting burrows are excavated in cut banks along the shoreline or stream edge. If suitable sites are not available, then man-made banks are utilized, including ditches, road cuts, gravel pits, and dredge piles. Nesting banks that attract colonies of Bank Swallows are also used by kingfishers. Occasionally old tree stumps or cavities in dead trees are used as nest sites (Kelly et al. 2009).

Data from the federal Breeding Bird Survey (BBS) were used to generate a North American population estimate of 1.7 million birds (Rosenberg et al. 2016). The size of Minnesota’s population is estimated at 20,000 birds, or 1.2% of the continental population (Partners in Flight Science Committee 2013).

Although its range of distribution is expansive, the Belted Kingfisher is a solitary species and is not present in high densities anywhere within its breeding range (Figure 1). In Minnesota, BBS volunteers reported an average of 0.4 kingfishers per route each year. This is only slightly higher than the survey-wide average of 0.3 birds per route. Because the species often maintains linear territories that follow shorelines, breeding densities are often reported as the number of birds per kilometer (km). Values range from 0.5 pairs per 1 km in Ohio (Brooks and Davis 1987) to 10 pairs per 1.6 km in New Brunswick (White 1953). One study, at Itasca State Park in Minnesota, estimated breeding density at 1 pair per 5 km² (Cornwell 1963).

On Minnesota’s two national forests, where forest birds have been monitored for 20 years, an average of 0.5 kingfishers were reported on 100 unlimited radius, 10 minute point counts from 1995 to 2010 on the Chippewa National Forest; and an average of 0.6 were reported on the Superior. This compares to an average of 210.5 Red-eyed Vireos on 100–10 minute point counts on the Chippewa and 224.8 Ovenbirds on the Superior, the most common birds on each respective forest (Niemi et al. 2016).

Although the BBS roadside surveys are not well suited to monitoring riparian species, they remain the only long-term data set for detecting population trends. The species’ relatively low abundance, however, results in population trend lines that lack precision, both at the national and state level. This caveat should be kept in mind when considering that the BBS data show that the Belted Kingfisher has declined an average of 1.37% per year survey-wide since 1966, and 1.85% per year in Minnesota since 1967 (Sauer et al. 2017).

As of the 2015 breeding season, there is no state, province, or region in the United States or Canada where the Belted Kingfisher’s population has increased. Overall, populations are estimated to have declined 49% since 1970 (Rosenberg et al. 2016). In light of this steady decline, the Partners in Flight Initiative established an objective to increase populations by 50% (Rich et al. 2004); in 2010 they also designated the species as a “Common Species in Steep Decline” (Berlanga et al. 2010) but removed it from the list in 2016 (Rosenberg et al. 2016).

Factors responsible for the decline have not been examined closely. Return rates of banded fledglings have been estimated as low, suggesting that mortality may be high for first-year birds; this estimate included a zero return rate for 46 fledglings banded in Minnesota (Kelly et al. 2009). Habitat loss and water quality degradation are also important factors for this aquatic-dependent species.

Given its decline and its relatively small population size, the Belted Kingfisher has been assigned a Continental Concern Score of 10/20 (Rosenberg et al. 2016). It has also been designated a Minnesota Species in Greatest Conservation Need (Minnesota Department of Natural Resources 2015).

Because the Belted Kingfisher is a fish-eating bird, accumulation of environmental toxins is of some concern. One study that examined eggs collected before and after the use of DDT showed the quality of the eggs was decreased during the years of DDT use but concluded the species reproductive success was not impaired (Fox 1974).

Despite its steady decline over the past 50 years, little management attention has been directed at the kingfisher. Perhaps the conservation measures that will benefit the species most are those that focus on improving water quality. Minnesota’s Clean Water Fund, a product of the 2008 Clean Water, Land and Legacy Amendment, provides significant funding to protect and restore the state’s water resources, including efforts to restore degraded and channelized streams. Restoration, management, and monitoring projects implemented with these new dollars should help species like the Belted Kingfisher that depend on clean waters. Forest management activities that insure protection of riparian zones are equally important.

In addition to the need for clean water, the availability of suitable nesting sites may be a limiting factor. Biologists in Wisconsin commented on the importance of quarry and road cuts for nesting in Wisconsin, particularly in northern counties, where kingfishers frequently forage around lakes that typically lack eroded banks suitable for nesting (Cutright et al. 2006). Certainly the same situation exists in Minnesota. Unfortunately, these man-made banks erode as they age and become less suitable for kingfishers. Protecting suitable nest sites may be an important conservation measure.

Finally, although the species has not been closely examined to assess its potential response to warming temperatures, initial reports rate its vulnerability to climate change as low (North American Bird Conservation Initiative 2010).