Breeding Bird Survey: frequently asked questions

BBS rules and data entry questions

Question: Why do observers have to send their route maps back to the BBS office every year, only to have them get sent back again the next spring?

Answer: The BBS office keeps two map files for every route in Canada. One file contains the current map and stop descriptions that are sent every year to the observer. The other file contains a copy of the current map and stop descriptions, as well as all old, altered maps and stop descriptions for the route. Though we are working towards having all maps available online for observers to download themselves, we ask observers to send back their maps every year. This is in case the route is reassigned to someone else; we will have a map to send to the new person. It also means that we can track any changes to your route or stop descriptions and ensure copies are made for the historical file. When observers don't return their maps, we have to make a photocopy from the historical file to send to out the next year, and we run the risk of providing out-of-date information.

Question: Do observers have to return the cover page (front page) that comes with the scannable data forms?

Answer: Yes please! The cover page contains information that must go in the BBS database. Even though some of this information can be recorded elsewhere on the data forms, without the cover page we cannot put your forms through the scanner. We then have to enter them via the Internet which takes much longer. In fact, we ask that you return any and all materials included in your yearly BBS package. This helps us cut down on waste as well as printing and filing costs.

Question: Why don't the species on the scan forms appear in alphabetical order?

Answer: We use the American Ornithologists' Union's order because it is in taxonomic order. Most field guides also organize birds by taxonomic order so that related birds are grouped together. This generally means that similar-looking species are grouped together, because often closely related species will resemble one another. When trying to identify a bird, it is always good practice to skim through nearby pages to see if there might be another bird that fits your description. If field guides were alphabetical, this would be much more difficult. And because field guides are in taxonomic order, it makes sense for the BBS to use the same order to make it easier to follow along.

Question: Could you add species to the list that appears on my data forms?

Answer: Each year, the United States Geological Survey uses an algorithm that pulls out the top 65 species for each route and prints them on the form based on abundance, number of stops detected, and how recently detected. If there are fewer than 65 species on a route, then all appear. If more than 65 species have been found on a route, then any new species must "outweigh" the old species before they appear on the form. This maximizes the likelihood that you won't have to add species in yourself. However, birds being what they are (i.e. mobile!), it is impossible to create a list that will fit perfectly every year, which is why we leave blank spaces in the forms so that species that are not on the list can be added.

Question: Why do I need to use Arabic numerals on my data sheets?

Answer: We send data sheets to the U.S. for electronic scanning if they are not entered online by the observer (which is the best case scenario since the observer is the only person who is familiar with their observations). The scanners can only recognize Arabic numerals. If the field sheets are not legible to the scanner, they are returned to the BBS office for manual entry. Arabic numerals are still important, as a "ll" used to indicate the count for various species can be very confusing. As some of these species can occur in large numbers at a given stop, the BBS office does not want to guess whether the observer means two or eleven.

Question: I can't access the United States Geological Survey (USGS) data entry site. What should I do?

Answer: Online data entry is on the USGS' BBS page. To navigate to the data entry section of the site, click on "Data Entry" in the lower middle of the page. Begin by following the directions provided for the pop-up blocker test to ensure pop-up blockers are temporarily turned off, because the data entry and review portal requires that pop-ups are allowed. Then click on "Data Entry and Review Portal v.3.0". You will see "Please login with…" and then 2 fields. Enter your username (the first letter of your last name following by 3 numbers; NOT the letter O) and your password, both of which were issued to you by the U.S. BBS office. Click "Login" to access your personal BBS page, which will allow you to enter and review your personal information and your route data. If you cannot remember your password or were never issued one, see FAQ on BBS password for data entry site. These steps should have resolved any issue, but if not, please contact the BBS National Office.

Question: I've never had a BBS password for the data entry site. What should I do?

Answer: A BBS password for the USGS data entry site should have been issued to all BBS participants. If you were never issued one or you have forgotten your password, click on the "Forgot your password?" link on the log-in page. On the next page, enter your observer number and the email address that the BBS has on file, and a new temporary password will be issued to you. This should then be entered into the password field on the login page. The easiest thing to do is copy and paste it in rather than retyping it because of some of the strange characters that are produced. A successful login will bring you to a new page where you will be required to replace the temporary password with a new personal password. Please create a new password according to the prompts on the page.

Question: I am in the midst of entering my data online but I can't seem to add "unidentified warbler" as a "new species". Why isn't it letting me?

Answer: As a general rule we do not enter unidentified species or species groups, but there are some exceptions. The few legitimate unidentified categories that exist are for areas where the overlap of closely-related species or subspecies sometimes makes it impossible to distinguish one from another by sound alone. An example is in areas where "Myrtle" Yellow-rumped Warblers overlap with "Audubon's". The BBS database allows you to enter them as Myrtles, Audubon's or "unidentified yellow-rumps", depending if you had a visual confirmation (the first two options) or only heard it (the latter option). This also holds true for the various junco and Northern Flicker "subspecies".

In all these cases, the "aggregate" data for the forms is used in our analyses, so the Myrtles, Audubon's and "unidentified yellow-rumps" can all be lumped together for analysis. However, there is no way to use such things as "unidentified warbler." There has been a case made for retaining "U.I. woodpecker", and "U.I. gull" has another history altogether. But, for the BBS, the term "unidentified" was never meant to be used for such generalities as "U.I warbler", duck, etc.). It is a shame to count a bird that you can't enter in the database, and we all have our share of those, but we hope that this explanation makes sense.

Question: I've already reviewed my data carefully. Why did I receive an email from the U.S. BBS office asking me to review again?

Answer: These emails are automatically generated as soon as you hit the "Submit" button. They are sent out for two reasons: 1) so that observers know that their data have been received, and 2) in case the observer didn't have a chance to thoroughly review the data and wants to take another look. If you know you've done a great job entering your data and you're sure that there are no errors, and then simply send us an email at indicating the fact that your route contains no errors.

Question: I think I may be losing my hearing. What should I do?

Answer: As we age, many of us lose the ability to hear high frequencies. We ask that observers with significant hearing loss, who find that they can no longer hear species they used to be able to hear, contact the National Office ( to discuss whether it is time to consider retiring from their route. Those with less significant losses should use their discretion and/or communicate with the National Office for more information. If you do decide to retire, this does not necessarily mean the end of your BBS career. We heartily encourage you to remain associated with your route, but as the assistant. That way, you can ensure that the stops the new observer uses are exactly the same as yours, and you can still enjoy the thrill of a morning spent conducting a BBS route. Retaining the exact same stop locations, year after year, is one of the best ways to ensure the strength of your route's dataset.

BBS route questions

Question: How are BBS routes designed? Why can't I create another route in my area?

Answer: Breeding Bird Survey routes are set up in a standard way so that the resulting data are as unbiased as possible and therefore suitable for statistical analyses. Here is how it works: Within a given province or territory, as long as roads are available, we try to place one route per one degree block of latitude and longitude. Once the first route in a block is assigned to an observer, we can then set up a second route to a maximum of four routes per degree block (this might be why you cannot create another route in your degree-block). To choose the precise location, we randomly select a point within the degree block and randomly select a direction of travel. From the random point we then move to the nearest available suitable road (usually a public secondary road). We would then go to the nearest intersection or other obvious landmark, if available. That becomes the starting point. The route follows that road as closely as possible in the randomly selected direction. It may turn onto other roads as it progresses if these will bring it closer to the random direction of travel. This method is meant, among other things, to prevent us from deliberately choosing routes that might go through areas that we think will have more birds, because this would bias the data.

Question: Part of my route is starting to feel unsafe due to increasing traffic or is so noisy that I'm afraid it might interfere with my ability to detect and count birds. What do I do?

Answer: Traffic is an ever-increasing problem on BBS routes. It may well be that we will have no choice but to alter this route so that it can be run safely. However, before we make a decision we need to clarify a few things. One of the strengths of the BBS is that data are collected from the same spots over many years. The longer the span of years that we can keep a route the same, the more valuable the data become. For this reason we need to be cautious when redesigning routes, changing them only when truly necessary. It is very difficult to judge when a route is no longer worth surveying because of noise. So far, our approach has been to encourage people to continue with their original route as long as possible unless they feel the road is unsafe. When safety or noise issues arise, we go through a series of steps to address the problem:

  1. We first ask whether conditions might be better on a different day of the week, such as Sunday, when there might be less traffic. Even if the amount of traffic decreases though, the problem of insufficient room to pull over may still be a factor. In that case, proceed to step 2.
  2. If you feel that there are stops that are temporarily unsafe or noisy (i.e. construction), please feel free to skip them (or move them forward or back by 0.16 km/ 0.1 miles) and document which stops were skipped or adjusted. This will not greatly impact the quality of your data.
  3. If a route must be modified, we first have to look for an option that would change the route by six or fewer stops. This way we have a chance of solving the problem while being able to maintain the route identity. If you feel that there are fewer than 6 stops that are permanently unsafe or noisy, please skip them, document which ones were skipped, and add them to the end of the route so that the total remains 50 stops. Please ensure that you update the stop descriptions to reflect these new stops so that the change can be well-documented at the BBS office.
  4. If you feel that there are more than 6 stops that are permanently unsafe or noisy, please contact the BBS office. If the cumulative changes to the route affect more than six stops we have to discontinue the route. The modified route then becomes a new route with a new name and number. Then it loses continuity with the previous route's data. When altering a route we strive to maintain the random nature of the route. BBS routes are established based on randomly selected starting points and directions of travel (see FAQ on Designing BBS Routes). While it is tempting to change a route to go through more interesting bird habitat, we have to be careful that any changes, whether for six stops or more, follow the original random choices as much as possible.

We encourage you to stick with the original route as long as you can unless you feel conditions are unsafe. We rely on observers to report field conditions to us, so please don't hesitate to share any further concerns you have with the BBS office.

Question: I cannot start at the official start point because of a washout, gate blockage, downed tree, etc., but the rest of the route is fine. What do I do?

Answer: It is always best to scout your route prior to the day you plan to collect data so that you won't be surprised by route closures or obstacles. However, if you didn't have a chance to scout your route, and discover on the survey day that you cannot start at the official start point of your route, begin your survey at the first stop that you can actually reach, and record your data according to the actual stop you are at. For instance, if a road is temporarily impassable from stop 1 - 4, begin your survey at stop 5, at approximately the time you would normally be at stop 5 if you had begun stop 1 at the official start time, and record your data from stop 5 onward. Please make a note of what happened and whether you think it is temporary or permanent.

If you believe the change to be permanent, the route will need to be adjusted. Please discuss this with the BBS national office. If a permanent change involves more than six stops we will have to consider the resulting route to be a new route, with a new name and number.

Question: I enjoy running this route but I live near the end point and have to drive along the entire route to start at the other end. Can I flip the route's direction?

Answer: Although we understand the desire to have the start point close to home, it is not possible to reverse the direction of stops. BBS routes are designed with a random start point (moved to the nearest usable road) and a random starting direction. This is an important part of the statistical design of the BBS and helps to avoid bias in the data by ensuring that the BBS randomly samples available habitat in an area. The only time we change stop locations on a route is if the road conditions make the route too dangerous for a car to stop or if traffic is so heavy that the noise interferes with the detection of birds (see FAQ on Route Changes due to Traffic and Noise) or if the road is blocked (see FAQ on Road Closures and Obstacles). Some observers go to within the vicinity of their route starting point the evening before. As you may know, observers can recoup some of these expenses for camping or hotels by submitting a claim to get a tax receipt totalling the amount they spent. We hope that these tips will encourage you to stick with your route!

BBS analytical questions

Question: What does the analysis estimate?

Answer: The analysis estimates trends (average annual rates of change, in percent/year) and annual indices of relative abundance (average expected number of birds observed on an average BBS route, run by an average BBS observer).

Question: What does the analysis control for?

Answer: The Canadian Wildlife Service annual trend analysis controls for: differences in observed abundance among observers and routes, start-up effects for the first year an observer runs a particular route, and variation in which routes are run in any given year. Methods are currently in development to control for potential changes in individual observers over time, such as hearing loss and/or improved identification skills. The analysis separately estimates trends and relative abundances among geographic regions (i.e., the geographic analysis strata). Other confounding factors are controlled for by the standardized BBS survey protocol, such as weather, time of day, and time of season.

Changes in habitat are not controlled because they, and the bird population changes that result, are one of the key environmental factors that the BBS survey is designed to monitor (see FAQ on Habitat Change).

Question: Does habitat change along BBS routes negatively affect the analysis?

Answer: Not at all. Changes in habitat are thought to be one of the most important drivers of trends and fluctuations in bird populations. BBS routes are, to the extent possible, designed to survey a representative sample of the regional bird populations and their habitat. The changes in habitat and in birds observed along a route over time are a small sample of the changes occurring across the regional landscape. The combination of these changes across all routes, and the variation in the changes among routes, allow us to estimate regional changes (i.e., the trend) and the uncertainty (or precision) around the estimate of regional change.

Question: If an observer misses a year on their BBS route, is the analysis affected?

Answer: Missing a year on a BBS route, as a result of poor weather, illness, or any other reason, is not ideal though sometimes unavoidable. However, it will not overly influence the annual status and trend analyses. In that year, it becomes slightly more difficult to accurately and precisely estimate the annual status of birds in your region. However, in any given year, it is usually only a small fraction of routes that go uncompleted, and the analysis is designed to account for this.

Question: I'm seeing fewer (or more) birds of a particular species but the species' trend for my region is positive (or negative). Why the difference?

Answer: The BBS is designed to estimate population status and trends for relatively large areas (e.g., trends for a province or Bird Conservation Region). The changes observed on any particular BBS route, or by any particular person, are a small sample of the changes observed across the entire region. Local effects, such as habitat change or other changes in human activity, can have a strong influence on birds in the vicinity of a single BBS route. However, these local changes may be balanced by opposite changes occurring in the vicinity of other routes. Our analysis is designed to get the best estimate of the average rate of change across the entire region.

Question: Are there trend estimates for individual routes?

Answer: No, the Canadian Wildlife Service does not estimate route-level trends. However, all BBS data, including the observations from any particular route(s), are available for download from the main BBS database, which is accessible through the USGS BBS website.

Question: What is a hierarchical Bayesian analysis, and how is it different from the old analysis?

Answer: The new analysis represents the latest step in the evolution of the Canadian Wildlife Service's statistical approach to estimating the status and trend of bird populations from the BBS. The hierarchical Bayesian framework has many advantages over previous approaches. This model in particular generates more precise estimates of trends that are less sensitive to the sampling variation inherent in a survey such as the BBS, which covers such a broad array of habitats and regions and involves many different observers. We have conducted a detailed comparison of the hierarchical Bayesian results with those from the previous analysis, which is available through the Canadian Field Naturalist.

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