excerpt from Introduction to the Species Accounts
The State List
We wrote accounts for each of the 422 species of birds that have been documented in Montana thus far. These species appear in the Montana Bird Distribution (MBD) database, and collectively they constitute the “official” list of the state’s birds. English and scientific names, and the arrangement of orders, families, and species, follow the seventh edition of the American Ornithologists’ Union’s (AOU) Check-list of North American Birds (AOU 1998) and subsequent supplements to the Check-list (which are published in the AOU’s scientific journal, The Auk).
The Montana Bird Records Committee (MBRC), established in 1991, accepted written reports for “Rare” species (documented fewer than 20 times in the state; Lenard et al. 2003) included in the book. The purpose of the MBRC is to evaluate reports of rare birds and maintain the official state list. According to the MBRC bylaws, a new species can be added to the state list only if it has been verified by a specimen or convincing photograph, or if the Committee accepts written documentation by two or more independent observers. Separate reports prepared by two people, each of whom scrutinized the bird and noted details of its appearance and relevant behavior, would be deemed independent for the purposes of the MBRC, even if the people were together when they observed the bird. A report written by someone who accompanied another observer but did not scrutinize the bird and note key field marks would not be considered independent documentation from the first observer’s report; neither would a single report submitted by a group of observers if only one group member made detailed observations of the bird.
The MBRC has struggled over whether its criteria for accepting a new state bird are too strict or too lenient. Some state records committees have accepted reports of new species on the basis of sight records by only one observer, whereas others require a specimen or unequivocal photograph, regardless of who (or how many people) observed the bird. The MBRC’s approach falls between these two ends of the documentation spectrum.
Appendix 1 provides an annotated list of “supplemental” species (often known as “hypothetical” species) that are not on the official state list. Evidence for the occurrence of these species is convincing, but in each case written documentation was available from only one independent observer, or else the origin of the bird in question was uncertain (e.g., escape from captivity could not be ruled out). Also included on the supplemental list are two species that are extinct in the wild. The supplemental list differs from previous such lists (i.e., Skaar 1980, Lenard et al. 2003) because we have omitted old records for which no information exists for review by the MBRC.
Comments on Evaluating Bird Records
Evaluating documentation of rare birds often is fraught with doubt, regardless of whether the submission in question ultimately is accepted or rejected. Most people who submit bird records are well intentioned, but time and again we have seen birders fall prey to self deception once they are convinced that their identification is correct (the “it couldn’t have been anything else, I’d stake my life on it” syndrome). This statement may seem ungracious, but we suspect that anyone who has served on a records committee knows precisely what we are talking about.
An unfortunate state of affairs that makes the job of records committees so difficult is that many observers do not take notes in the field, and an ironclad report for a rare bird can be generated easily after the fact with the aid of a good field guide. Consequently, we believe that anyone charged with evaluating bird sightings should strive to err on the side of omission versus commission, given that evaluation errors are inevitable. That is, if sufficient doubt exists, it is better to reject what may have been a valid report of a species than to accept a record of a bird that has been misidentified. After all, for every thoroughly documented occurrence of a rare bird, untold numbers of occurrences of other rarities go unnoticed, especially in a large and sparsely populated state like Montana. One can never be aware of every occurrence of a vagrant in a particular area, and nothing can be done about that fact. What one can strive to avoid, however, is accepting a record that is in error. This is accomplished by adhering to strict guidelines established by records committees. The result of such adherence is that some observers may become offended (even in cases where a report is accepted), and records committees are constantly challenged to uphold their standards without discouraging or putting off people who submit reports with good intentions but nonetheless have a submission rejected now and then. Dittman and Lasley (1992) provide excellent advice on how to properly document sightings of rare birds.
Contents of the Species Accounts
Each species account begins with an introduction that contains a natural history anecdote or two and information on the species’ global distribution followed by a section entitled Status & Occurrence (relative abundance, frequency of occurrence, seasonal occurrence, Montana distribution, timing of migration and other annual-cycle events). If the species is not monotypic, we also list the subspecies that occur(s) in Montana. Accounts for species that regularly occur in Montana also include sections on Habitat (habitat preferences for foraging and nesting), Conservation (conservation status and issues; information on population trends, where appropriate), Historical Notes (where possible, information drawn from Montana studies conducted during the 19th to early 20th centuries), and Contemporary Work (selected aspects of the species’ ecology or conservation based where possible on work conducted in Montana since 1950). Range maps are provided for regular breeders and some of the wintering species. Accounts for species that do not occur regularly in the state do not necessarily include each of the sections identified above.
Regarding conservation status, we identify whether the species is classified under one of the following lists: Montana Priority Bird Species (Casey 2000), State of Montana Species of Concern, U.S. Fish and Wildlife Service Threatened and Endangered Wildlife, and BirdLife International’s Threatened Birds of the World (BirdLife International 2004). The Montana Priority Bird Species List is based on the Partners in Flight (PIF) prioritization process and contains 107 species: 14 species at priority level I, 42 species at priority level II, and 51 species at priority level III. Species at level I generally exhibit declining population trends and warrant immediate conservation action. Level II species are not thought to be at as high a risk as those at level I but nonetheless are in need of monitoring to assess population status. Species at level III are not at imminent risk statewide but may be of local concern and/or occur in high-priority habitats that themselves are at risk (e.g., Sage Thrasher in sagebrush steppe, Song Sparrow in riparian woodland). See Casey (2000) for a detailed account of the PIF prioritization process in Montana.
Relative Abundance, Frequency of Occurrence, and Seasonal Occurrence
There are no hard-and-fast rules on how to define relative abundance for a species over a large geographic area, despite the useful attempt at standardization first put forth by Arbib (1957). We have followed what seems to be a common practice among state bird books (e.g., Zeranski and Baptist 1990, Hess et al. 2000, McWilliams and Brauning 2000): set abundance definitions based on an arbitrary number of individuals that a skilled observer might expect to see or hear during a day afield and trust that readers will have a feel for what we are trying to convey. We take this approach reluctantly for two reasons. First, assessing abundance based on the number of individuals one might encounter in the field necessarily presumes that the ability of different observers is similar. In reality, of course, abilities vary widely among observers, even if the field is narrowed to skilled ones. Second, conspicuousness, and thus probability of detection, differ tremendously among bird species (e.g., Swainson’s Hawks are easier to see than Northern Goshawks, and House Wrens easier than Sedge Wrens). Nonetheless, relative abundance must be defined, so we offer the following definitions, with abundance categories in bold. In the habitat(s) where a species normally occurs, and at the proper time of year, a day of birding by an experienced observer should yield more than 100 individuals of an Abundant species, 26-100 individuals of a Common species, 6-25 of a Fairly Common species, and up to 5 of an Uncommon species. As noted above, a species is officially Rare if it has been documented in the state fewer than 20 times. Some species with a restricted range in Montana are Rare only because they have been under-reported; we define these species as Locally Fairly Common (e.g., Blue-gray Gnatcatcher, Sage Sparrow).
So far as frequency of occurrence is concerned, species that are classified into one of the first four abundance categories above (Uncommon to Abundant) occur in the state regularly, and we see no reason to mention this in the species accounts. However, for species that are less common than Uncommon, and that are not necessarily found in Montana every year, additional terms are useful. Combined with one of the seasonal occurrence categories defined in the next paragraph, we use Occasional for species that have been recorded in Montana 20 or more times but may not occur regularly (e.g., Barn Owl, Northern Hawk Owl), and Casual for species that have been recorded fewer than 20 times but that occasionally breed (e.g., Black-throated Gray Warbler, Lesser Goldfinch). Finally, we use Vagrant for species whose normal ranges are outside of Montana, and which have been documented in the state fewer than 10 times; these species are also officially Rare.
For seasonal occurrence, a species is a Permanent Resident if it occurs in Montana year-round and breeds, even if some breeding individuals migrate out of the state to winter elsewhere, or if some wintering individuals breed elsewhere (e.g., Red-tailed Hawk, American Robin). A Breeding Resident nests in the state and normally winters elsewhere (e.g., Flammulated Owl, Ovenbird), and a Winter Visitor spends at least part of the winter in Montana but breeds elsewhere (e.g., Glaucous Gull, Snow Bunting). A Migrant passes through the state while en route to its breeding or wintering grounds elsewhere, usually but not always moving through Montana twice each year (e.g., Stilt Sandpiper, Blackpoll Warbler).
Sources of Information
We consulted hundreds of publications while preparing this book. Several were especially helpful and merit mention here. First is the pioneering work of Saunders (1921), which is discussed in more detail in the history chapter. Cliff Davis’s (1961) dissertation also was useful in pointing us toward much of the historical literature on Montana birds. Dave Skaar’s (1969) Birds of the Bozeman Latilong set the stage for what would become Montana Bird Distribution (Skaar 1975), now in its 6th edition, with new editions appearing roughly every five years. Also worthy of mention are Larry Thompson’s (1985) scholarly work on Montana explorers and the superb bibliography on early naturalists and expeditions in Montana by Craig and Pam Knowles (1995). We obtained much of the information on rare species from the excellent summary completed by Phil Wright shortly before he died (Wright 1996). Dan Casey’s (2000) PIF plan for Montana birds was very useful in identifying key conservation issues in the state. It would be difficult to contemplate undertaking a work such as this without the availability of these foundational publications.
The Montana Bird Distribution (MBD) database is a repository for bird records that was created in 1991 as a joint project of Montana Audubon, Montana Fish, Wildlife & Parks, and the Montana Natural Heritage Program. The online database, which is maintained by the Heritage Program, contains nearly 400,000 records that were submitted by thousands of observers. This database has been indispensable to our work. We also made repeated use of the U.S. Geological Survey’s (USGS) Breeding Bird Survey (BBS) database to examine population trends for selected species (Sauer et al. 2007). BBS routes are run in June or July across the U.S. and Canada. Each route is 24.5 miles long (ca. 40 km) and laid out along a road, with stops every 0.5 miles (thus 50 stops per route). At each stop, the observer gets out of the vehicle, waits about a minute for things to settle down, and then records all birds detected by sight or sound for 3 minutes. Routes are run in the same place year after year, preferably by the same skilled observer to maintain continuity. As of 2005, 68 BBS routes are surveyed annually in Montana (see Appendix 2). Estimates of population trends (up, down, or neutral) for species detected on BBS routes are derived by averaging the number of birds per route over multiple years in a state or larger geographic area. Trend estimates are useful for comparative purposes and can provide important information on the potential for a species (or group of species, such as grassland birds or Neotropical migrants) to be of conservation concern. We also obtained information on recoveries of banded birds from the USGS Bird Banding Laboratory, although we did not perform an exhaustive analysis of banding data for any species.
A Word on Arrival and Departure Dates
High-quality data on arrival and departure dates are difficult to obtain. Normally, they can be
gathered only by non-casual observers (if a wide range of species is to be covered) who monitor
the same areas year after year and who must be present throughout the ranges of arrival and
departure dates for the suite of species being surveyed.
Examination of three long-term data sets reveals that arrival and departure dates can vary
tremendously across Montana (Table 1; note that one data set is for extremes in arrival dates
only). Indeed, they can also vary quite a bit among years for the same species at a single locale
(see last column of Table 1). Consequently, in most of the species accounts we treat timing of
arrival and departure in rather general terms rather than attempt to provide “average” dates, or to
ferret out extreme dates for the state.
Abbreviations and Acronyms
Despite having worked for state and federal agencies for many years, we are not big fans of acronyms. Yet, they are useful if applied sparingly, and they also help to save space. The following abbreviations and acronyms are used throughout the species accounts.
AB, American Birds
ABC, American Bird Conservancy
AFN, Audubon Field Notes
AMNH, American Museum of Natural History
AOU, American Ornithologists’ Union
BBL, Bird Banding Laboratory
BBS, Breeding Bird Survey
c., central
CBC, Christmas Bird Count
Co., County
Cr., creek
e., eastern
ec., east-central
FMNH, Field Museum of Natural History
ha, hectare(s)
I(s)., Island(s)
IBA, Important Bird Area
km, kilometer(s)
m, meter(s)
MBD, Montana Bird Distribution
MBRC, Montana Bird Records Committee
MSUZM, Montana State University Zoology Museum
Mt(s)., Mountain(s)
MVZ, Museum of Vertebrate Zoology (Berkeley)
n., northern
NASFN, National Audubon Society Field Notes
nc., north-central
ne., northeastern
NF, National Forest
NP, National Park
nw., northwestern
NWR, National Wildlife Refuge
OSUZM, Oregon State University Zoology Museum
pers. comm., personal communication
pers. obs., personal observation
PIF, Partners in Flight
R., River
Res., Reservoir
ROM, Royal Ontario Museum
s., southern
sc., south-central
se., southeastern
SP., State Park
sw., southwestern
UMW, University of Montana Western Bird Collection
UMZM, University of Montana Zoology Museum
unpubl., unpublished
USDA, United States Department of Agriculture
USFWS, United States Fish and Wildlife Service
USGS, United States Geological Survey
USNM, United States National Museum
w., western
wc., west-central
WMA, Wildlife Management Area
WPA, Waterfowl Production Area
Copyright Notice: © 2008, Jeffrey S. Marks, All Rights Reserved