Range maps can be invaluable tools to identify birds, and birders who are familiar with bird ranges can easily use maps to be confident with their bird identifications.
Where to Find Range Maps
Range maps are commonly included in field guides, though the sizes, colors and level of detail on each map may vary from guide to guide. In many guides, maps are found with each bird's description and photos or illustrations, while other guides may group all range maps together in a common index. Online bird profiles may also have range maps available, and ornithological references may feature highly detailed range maps that may show additional information, such as changes in a species' range over time or the relative density of populations in different areas.
Using Bird Maps for Identification
With just a few steps, it is easy to use range maps to help identify birds.
- Check Before Birding: To get an idea of what birds you may see in a particular range, study range maps before heading into the field. This is especially useful for birders who plan to go bird watching on vacation or who are traveling to a birding festival, since they are likely to encounter many unfamiliar species. Getting an idea of what to expect before birding can help you identify birds more quickly even if you've never seen them before.
- Compare Seasons: The same birds may be found in vastly different areas in different seasons. Range maps can help pinpoint roughly when a bird should be in one area, making it easier to identify birds seasonally. This is especially helpful for winter birds when they are in non-breeding plumage and may be more difficult to tell apart, and comparing species by range can be a deciding factor in a proper identification.
- Note Similar Species: Most field guides group similar birds together on the same page or in the same section, making it easy to compare them visually to check field marks. Comparing range maps in the same way can help birders learn where visually similar birds may be, and in some cases, can help eliminate some of the most confusing identification problems immediately when the birds do not inhabit nearby ranges.
- Compare Several Maps: Different field guides and other birding resources may have slightly different maps covering bird ranges, especially when comparing older maps and newer resources. Checking several maps can give birders a more complete idea of a species' range and can be useful for making identification decisions, particularly near the edges of a range or where similar birds' ranges overlap.
Range Maps Aren't Perfect
It can be tempting to consider a range map as an absolute authority on where and when birds should be present, but range maps can be flawed. Bird ranges change frequently, and an older or less detailed map may not cover recent population changes or shifts. Similarly, birds are often spotted outside their expected ranges either as vagrant birds or because they have been introduced to new areas. Over time, introduced birds can form isolated new ranges where they are successfully breeding, and those ranges will continue to grow as the birds thrive, even if they are far from their native range.
By understanding the pros and cons of bird range maps, savvy birders can use them as tools for proper bird identification and finding even more bird species to add to a life list.
Photo – Least Flycatcher © Nick Saunders