A bird checklist is a list of all the different bird species which occur within a specific area. It’s called a checklist because it has evolved into a standardized format in which the order of bird species on the list follows an industry standard and each species can be checked off as you see them. (In some birding circles, each bird on the checklist is ‘ticked’ as it is encountered, with each species then referred to as a ‘tick’).

Our level of knowledge about the birds of North America is now so good that virtually every politically-defined region (i.e., state, county, province, national park, etc.) has a bird checklist specific to that region. And with the rise in the popularity of the internet, it is relatively easy to get hold of a checklist no matter what region of the continent you are in or are planning to visit.

Order of birds

The bird species in a checklist are placed in phylogenetic order, which means that the first bird on the list is a species that has evolved (i.e., changed over time as compared to its ancestor) the least and the last bird species is one which has evolved the most. For example, on the Checklist of North American Birds, the first bird is the Great Tinamou and the last bird is the Pin-tailed Whydah.

This checklist, which is the most comprehensive checklist for birds in North and Central America with 2046 species, is maintained by the American Ornithologist’s Union, a renowned scientific organization devoted to the study of birds. It can be viewed as the starting point for every other checklist in North America, with all of the birds in the same order, but with varying numbers of species depending on the region covered by the checklist.

The number of species on a checklist depends on the region covered by that checklist. A small city may have a checklist with less than 200 species whereas a natural area which is a significant site for birds may have up to 400 species. Generally, the further north you are in North America, the fewer species you will encounter, due to decreasing diversity of birds with an increase in latitude from the tropics to the polar regions.

Types of checklists

The most basic checklist is one which simply lists all of the birds seen in one region during the course of a year. Checklists have generally been refined over the past few decades such that they can be considered an accurate document of that region’s bird life. Since bird populations are dynamic (that is, they change in response to changes in the environment) it is possible to add new species to a checklist because that species has expanded its range.

A recent example of this is the House Finch, which has been steadily expanding its overall range in North America northwards into Canada, such that places where they had never been recorded just a few years ago now have breeding populations and they are even becoming a common sight.

More detailed checklists will include information about each species. The most common information is the inclusion of life history codes, which describe what the bird is doing in that region. Some of these codes include:

R = resident (bird is present year round).

B = breeding (bird found in this region only during the breeding season).

M = migrant (bird migrates through the region).

W = winter resident (bird is present only during the winter season).

A = accidental (bird is not normally found in the region).

There are also checklists which have been modified for specific uses or projects, such as breeding bird atlases (see below) and biodiversity monitoring programs. In short, a bird checklist can be modified in virtually any way you want.

Who uses checklists

In a word, everybody. Their uses can range from educating birders who are new to a region and want a quick way to learn about the different bird life they are encountering, to experienced birders who have been using them for many years as a way to keep track of which species they have recorded on each outing.

It is not unusual for the car of an experienced birder to have a pile of different checklists in the back seat, one for each area they may be driving through on the weekend.

Programs which use checklists

There are a number of citizen science programs which use checklists as the most efficient method for collecting information. A breeding bird atlas program, which seeks to produce range  maps for every species breeding within a region, will have customized checklists which include places for making notations about the breeding status of a bird (e.g., possible, potential or confirmed breeding).

A program which is becoming more popular is a regional checklist program. It has been demonstrated that the composition of the bird community in an area over the course of the year can be acurately determined by having birders fill out a basic checklist each time they are out birding. Once several thousand checklists have been sent in by participating birders, the information can be compiled into a database and analyzed to show, for example, which species are present during each week of the year.

It should be pretty obvious by now that checklists are not only very useful tools in learning about birds but they can also be used as the foundation to increasing our understanding of bird communities across the continent.