Rare Bird Documentation

At some point in your birding experiences you may encounter a bird that is not usually found where you are seeing it. A bird that is lost or confused and wandering far away from where it should be. What should a birder do when he/she sees a bird they think is unusual?

Well, the answer, in part, believe it or not begins before the birder even sets foot in the outdoors. Here is a brief overview of the rare bird documentation process, followed by more in depth details and several examples as suggestions.

First, familiarize yourself with the expected birds, at that time of year, for the location/habitat you intend to bird.

Second, find a way to record as many pertinent details as you can about the bird, WHILE YOU ARE OBSERVING IT! If at all possible record the bird via audio recording, photographs and/or video. Modern cell phones have apps/features that make this easy to do.

Third, get the word out, sooner rather than later.

Lastly, as soon as you have the opportunity, write out a detailed description of your rare bird.

(Credit to the Indiana Audubon Society and the Indiana Bird Records Committee for much of the content below.)


Once hooked by the bird watching bug, birders will tend to start noticing birds in more places. As a birder's knowledge base grows, nuances they were formerly oblivious to, such as bird age, sex and plumage, gradually add to the complexity of the birds they see. Eventually, their local patch bird list expands to include other nearby bird spot residents. They may even go so far as to take time while traveling or visiting family, to look for new birds there. So, how does a birder, experienced or beginner, know when a bird they are seeing is usual or something rare? There are two main types of resources available to birders to help learn about the local birds; printed regional bird guides and online digital resources.

  1. Regional Bird Guides - Locally there are published birding guides:

    • San Joaquin County - The San Joaquin Audubon Society has published Birding San Joaquin County. This guide is a description of the region and its birds and was updated in late 2019.

    • Stanislaus and Merced Counties - The Stanislaus Audubon Society has published The Birding Sites of Stanislaus and Merced Counties. It also has several updates and can be found online.

  2. eBird Hot Spot Bar Graphs - Become familiar with the planned birding location ahead of time by using the resources available through eBird. Visit the eBird hot spot and see what has been observed lately. Visit the hot spot bar graphs which can be filtered to the exact time of year that you will be there. Note: Bar graphs are available at the county/state/country level, as well as for individual hot spots. All can be refined by month in question.

  3. Merlin Bird App - Merlin is a customizable field guide app for birds around the world. Get identification help and discover what birds to look for near you with Merlin Bird ID.

Make sure you have the most up-to-date version of your birding apps on your smartphone. eBird and Merlin are updated often, and these updates are readily available (free) in your phone app store.


It is important to include only those field marks that you actually observe, not what you think should be there or what someone tells you that they saw or what your field guide tells you you should have seen. It is also important to note things that you looked for, but did not observe. If you were documenting that a small, dark goose is a Brant, rather than the more common Cackling Goose, it would be important to note that you looked for the white chinstrap of the Cackling, but it was not present on your bird. It’s important to record even the most minute details that you see, as they may matter in differentiating one species from another. Of course, no one is going to remember or record everything. Just do the best that you can!

  1. Jot down details on a notepad.

  2. Photograph and/or video record the bird

  3. Use your smart phone to record the audio

  4. Narrate details using your smart phone

What details should be included?

  1. Include physical features clearly seen, such as relative size, body shape, tail and bill lengths. Color and patterns of the head, wings and tail.

  2. Describe the behavior of the bird, noting any unusual movement, feeding or flight patterns.

  3. Listen carefully to any vocalizations. Attempt to compare the calls/sounds to something you are familiar with.

  4. Location details. Note the temperature, wind, lighting and sun location relative to your direction viewing the bird. How far away was the bird. What optics did you use. Did others see the bird.

Most people tend to emphasize the color of the bird when recording details, but other aspects may be just as important, or even more important. Body size is always a handy thing to note. When birding, this virtually always means a relative size: the bird you saw was as big as or as small as other birds with which it was observed. Actual size is difficult for most people to estimate without some frame of reference. In fact, it may be challenging to get an actual size unless you have the bird in hand and measure it. Since many species that are difficult to separate may differ in actual size by only fractions of an inch, guessing at a bird’s actual dimensions may be worthless.

Shape of the bill, wings, and other parts are also useful in differentiating some birds so include this in your notes. Many birders look at bill shape first to identify an unusual bird, since the bill often tells you what group a bird belongs to. In 2002, a difficult bird appeared in the Indianapolis area and speculation centered on whether the bird was an immature gull or some kind of duck. These two groups have very different bills, and that could have settled that part of the debate easily. [The bird turned out to be an exotic species of duck.]

Plumage coloration is one of the most diagnostic marks available in identification of avian species. Take meticulous notes on the colors of the back, underparts, wings and tail of the bird being studied. Be as accurate about the colors as possible. “Is it light gray or dark gray?” or better yet, if you’re familiar with color charts, use those to pin down the exact color of gray. Just be sure to include whose color chart you use. All of the field guides give a description of the various parts of the bird often in the beginning of the guides. Become familiar with these terms and use them to make an accurate description. David Sibley’s Birding Basics also provides an excellent description of the parts of birds. There are differences between wing bars versus wing stripes and eyebrows versus eye lines. Improper use of terms can lead to future confusion on the part of everyone. The size, shape and color of soft parts (non-feathered areas such as the bill, legs and eyes) are also vital pieces of information. All of the above information that applies to plumage is relevant to describing soft parts as well.

Behavior is an important aid to bird identification. How was the bird acting – how would you describe its flight, feeding, or other behavior? Bird flight can tell a lot about a bird. Is the flight rapid and smooth or slow and floppy? Did the bird hover? Are the wings pointed or round, and is the tail forked or square in flight? Can you observe any additional field marks when the bird was flying that you couldn’t see when the bird was at rest?

Did the bird vocalize while you were watching it? This doesn’t mean just singing, but did it make any calls such as chips or alarm calls. What else did the bird do while you watched it? Was it feeding? Was it gathering nest material or food? Did you find a nest? Was it interacting with other species of birds? If so, what kind and how many? What type of habitat was it located in: old field, deep woods, marsh, etc.? While habitat is not diagnostic, it is an indicator in certain situations.


  1. Post on a local listserve

  1. Call or text local birders (if known)

  2. Post an eBird checklist with as much detail as possible as soon as possible. If your ID is not yet 100%, feel free to include wording such as "probable, but not yet confirmed" in the bird notes on eBird. Remember, you can always go back later and edit your eBird report if you recall more details or if you wish to delete something from your original report!


  1. Complete a rare bird documentation form (or other similar format) as soon as you have the opportunity. Write out a detailed description of your rare bird using your field notes and your memories (while they are still fresh in your mind). Fill in as much of the documentation form as you can, without the aid of other references that could influence your writing.
    Link to Stanislaus County Rare Bird Documentation form Word doc (download and complete).
    Link to San Joaquin County Rare Bird Documentation form (coming soon).

  2. Once this is done, you can dig into your reference library and compare the bird that you saw with other similar species. Explain, as fully as possible, why the bird that you saw cannot be any of these. This is where all of the detailed notes that you took will be invaluable. List the materials consulted to eliminate similar species.




While conducting a bird survey at the San Joaquin River NWR, Page Lake complex, I saw a smallish yellowlegs-type shorebird with long yellowish green legs about 90 yards away along the edge of an inlet to the "lake." It immediately got my attention as it seemed shorter and more slender than a Lesser Yellowlegs. I barely got my camera on it for a couple of quick shots when it took flight. I caught a couple of shots of it in flight. I could clearly distinguish its call note of "tew tew, tew tew, tew tew" as it flew away. It settled down about 150 yards away and allowed me to get my scope on it. The bird eventually flew off towards the NW. I contacted another of the U.S. F & W volunteers to come out and help document it. About 45 minutes later I returned with Richard Brown to the original spot and the bird was back again. We both got more documentation photos and it again took off towards the NW. I circled around the pond and saw it just inside of a flooded corn field. I took several more images before it took off and headed back to the original location. At this point we left the bird alone as we had more than sufficient documentation.


The bird was similar to, but noticeably smaller than, other yellowlegs with a medium-long bill, light throat and belly. The top of the head, across its neck and back were a medium brown with some light spots. The wings were slightly darker brown with few spots. The legs were yellowish green and the bill was yellowish tan at the base, becoming darker towards the tip. The eyes had a very distinctive white ring, much bolder than any Lesser Yellowlegs. It also had a slight white line running from the eye towards the base of the bill. In flight, the base of the upper tail and center of the tail feathers was dark compared with the all-white rump and tail of a Lesser (or Greater) Yellowlegs.


Comparisons of my field notes and multiple good photos clearly show the Solitary Sandpiper had dark upper tail feathers and dark central tail feathers which eliminated either of the yellowlegs species. Additional support details include the bold eyering and the in flight calls. According to the Cornell Lab Birds of the World, Solitary Sandpipers give a call note of 2 syllables when they are simply changing position at an existing site.


Date & Time: 7/24/2020 9:00 am until 10:30 am (off and on)

Optics Used: 10x50 binoculars and 60x telescope

Distance from Bird: Initially 90 yards, then 150 yards, then about 20 yards.

Conditions: The sun was to my right with clear skies and calm winds.

Species ID: 100% certain Solitary Sandpiper

Age/sex: Juvenal based on the absence of distinct spotting the the wing.

PHOTOS: (below)