Ruby-crowned Kinglet (Regulus calendula) Zach Gayk
Macomb Co., MI September, 2008. © Willie McHale
(Click to view a comparison of Atlas I to II)
Distribution A familiar migrant across North America in The historical breeding range of Ruby-crowned nearly any habitat, this diminutive hover-gleaner Kinglet prior to the early 1900s remains largely retreats to the cool, mosquito-infested bogs of unknown, but is assumed to be very similar to northern Michigan during summer, where its that of the present range. While Barrows (1912) piercingly rich song drifts down from the did not classify Ruby-crowned Kinglet as a pointed spires of tall black spruce trees. Michigan breeder, and the species was Wintering across the southern U.S. from the described as rare and local in Michigan by Carolinas to California, and extending into Zimmerman and Van Tyne (1959), these status southern Mexico, Ruby-crowned Kinglets may classifications are most likely due to the fact also winter as far north as southern that the Ruby-crowned Kinglet was easily Pennsylvania, Connecticut, and Illinois in the overlooked in the remote boreal forests of its east and Midwest, and coastal Washington and breeding grounds by early observers. In MBBA Oregon in the west. The northern limit of its I, Ruby-crowned Kinglet was recorded as at winter range appears to be strongly correlated least possibly breeding from 29% of UP with the -4ºC January temperature isotherm townships and 2.7% of LP townships. In (Root 1988). In summer it extends from central MBBA II, Ruby-crowned Kinglet was recorded Alaska south through British Columbia and as at least possibly breeding from 28% of UP Washington and into the Rocky Mountain states townships and 1.8% of NLP townships. This as far south as southern New Mexico and east corresponds to a 1% and 0.8% decrease in atlas across Canada, largely excluding the prairie township detections in the UP and LP provinces and states into northern Minnesota, respectively. Statewide distribution remains Wisconsin, and Michigan, and New England. In similar between the two atlases, with the Michigan, Ruby-crowned Kinglet is an majority of confirmations and probable records uncommon breeder in the UP and a rare breeder coming from three distinct regions: the in the NLP. Michigamme Highlands of western Marquette and eastern Baraga Counties, the eastern UP’s peatland region comprising northern Luce, Chippewa, and southern Mackinac Counties, and the Keweenaw Peninsula. There was a
© 2011 Kalamazoo Nature Center Ruby-crowned Kinglet (Regulus calendula) Zach Gayk notable decrease in probable records from (Keweenaw County) in the UP were visiting Dickinson County between MBBA I and active nests (Binford 2006). Eleven nests found MBBA II. In the LP, reported observations of in Algonquin Provincial Park, Ontario were Ruby-crowned Kinglet are largely clustered in located at an average height of 12.0 meters the north-central and north-west regions. In within black and white spruce with an average MBBA I, only one confirmation was reported in height of 16.0 meters, on limbs 1.7-2.5 meters Cheboygan County, while a probable record from the trunk (Simon et al. 2003). The nest, from Clinton County in the southern LP which is located within clumps of dense, constituted the southern-most atlas detection in overhanging foliage, is constructed largely of both atlases. In MBBA II, the two sole reported mosses, lichens, grasses, and conifer twigs so as LP confirmations were from Cheboygan and to allow for elasticity as the brood grows Charlevoix Counties. (Thaler 1976). Adult males may prefer tall extra-canopy spruce higher than the surrounding In the UP, Ruby-crowned Kinglet is found forest as singing locations (pers. obs.). breeding at highest densities in closed canopy black spruce bog, often mixed with tamarack Abundance and Population Trends and near water (Binford 2006). Less frequently, (Click to view trends from the BBS) it may inhabit small conifer swamps of white The PIF Landbird Population Estimates cedar and white spruce, often along creeks, Database estimates the global Ruby-crowned within unsuitable mesic deciduous or mixed Kinglet population to be 70,000,000 individuals forest (pers. obs.). While inhabited black spruce of which Michigan’s estimated 40,000 comprise stands tend to be dense (Lance and Howell 0.1% (PIF 2008). In MBBA I, there were 177 2000), territories are often located at the edges township detections in the UP and 16 in the LP, of small unforested bog openings. Ruby- with 14 of the LP detections from the NLP. In crowned Kinglets also appear to prefer mature MBBA II, the UP had 174 township detections spruce forests to younger stands in in the UP and 12 township detections in the LP, Saskatchewan (Hobson and Bayne 2000). In a with eleven of these from the NLP. This data survey of Bete Grise Preserve in Keweenaw indicates a slight range decrease in Michigan County, 26 Ruby-crowned Kinglets detected between MBBA I and MBBA II that may within the 1,104 acre tract were most frequently simply be attributable to differences in observer found within dense 50-60 ft tall black spruce- effort and coverage between the two atlases. tamarack forest with undergrowth of ericaceous BBS trend data, however, indicates a plants such as Labrador tea, and blueberry along statistically significant 5.14% decrease in Ruby- ridges bisecting unforested fens (Gayk 2008). crowned Kinglets reported on BBS survey routes in FWS Region 3 (which comprises the Breeding Biology Midwest), (Sauer et al. 2008). Because boreal Pair formation is assumed to take place from and bog forests are not increasing in area in late April to the first week of May (Swanson et Michigan, it is likely that Ruby-crowned al. 2008). There is a noted dearth of nest records Kinglet is either remaining fairly constant or for this species relative to its uncommon status decreasing slightly in range and abundance in that most likely is due to its treetop nesting Michigan. habits. In Ontario, the earliest nest was found on 12 May, with an incubating female on 30 May Conservation Needs (Swanson et al. 2008). Adults observed Like a host of passerine species closely tied to carrying food on 15 June (Houghton County), boreal forests in Michigan, the Ruby-crowned 24 June (Baraga County), and 2 July Kinglet’s Michigan distribution and abundance is heavily dependent on the amount of mature,
© 2011 Kalamazoo Nature Center Ruby-crowned Kinglet (Regulus calendula) Zach Gayk black spruce forest in Michigan. Timber 5.15.2008. USGS Patuxent Wildlife harvest, which tends to consist of clearcutting in Research Center, Laurel, MD the black spruce forest habitat type, has adverse Simon, N.P.P., A.W. Diamond, and F.E. effects on Ruby-crowned Kinglets. The Schwab. 2003. Do northern forest bird establishment of boreal forest preserves communities show more ecological protected from timber cutting, and the plasticity than southern forest bird development of management plans in state and communities in eastern Canada? Ecoscience national forests that decrease the amount of 10(3):289-296. clearcutting in boreal black spruce forest is Swanson, D.L., J.L. Ingold and G.E. Wallace. crucial to this species’ survival in Michigan. 2008. Ruby-crowned Kinglet (Regulus calendula) In The Birds of North America Literature Cited Online No. 119 (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from Barrows, W.B. 1912. Michigan Bird Life. the Birds of North America Online: Special Bulletin. Michigan Agricultural
© 2011 Kalamazoo Nature Center