Ratings increase the utility of Macaulay Library media for everyone, enabling the best images, audio, and video to be discovered and used in projects such as Merlin and Birds of the World, as well as Illustrated Checklists and external research applications.
You can rate your own media when you add it to your eBird checklist, as well as any photo, audio recording, or video that you find in the Macaulay Library. We use a 5-star rating system, with 5 stars being the highest quality.
For all three media types, keep in mind that the rating should be based on the technical quality, not the rarity of the bird. Biological interest should not play a role in the star rating. Please rate media honestly; attempts to manipulate the rating system or use multiple personal accounts to rate media is not allowed.
Rate the quality of the image, not the quality of the bird or the observation. A great photo of a common, drab bird should still be 5 stars and a poor photo of a very rare or hard-to-photograph bird could still be only 1 or 2 stars. When rating, please consider the photo guidelines, as well as the following factors:
- Sharpness: Is the primary subject in focus? Is the image blurred or grainy?
- Visibility of bird: How well can you see the bird? If the bird is very small, partially obstructed from view, or backlit in the photo, the rating should be lower than it would be otherwise.
- Size of photo: Downrate any photo that has a noticeably small resolution. When possible, photos should be at least 1600 pixels on the long side, and full resolution files are encouraged.
- Watermarks: Downrate 1-4 stars depending on the size and obtrusiveness of the watermark.
- Composite photos, back-of-camera, photos with obtrusive graphics or extreme editing: automatic 1-star for anything that is in clear violation of photo guidelines
- Flocks: Rate flocks based on the quality of the image rather than the visibility of any individual birds. Is the flock in focus, well lit, and the overall image of high resolution?
Rating videos is similar to rating photos, with some additional aspects that may change your rating. When rating videos, please consider the following factors:
- Visibility of the subject in frame: Does the bird fill a reasonable amount of the frame? Very wide shots where the bird is small are still useful but shouldn't receive 4 or 5-star ratings. On the other hand, a video doesn't have to be a frame-filling head shot to be 5 stars. Videos that show the full body of a bird as well as some habitat around them are among the most important for illustrating behavior.
- Stability: Is the video stable and not shaky or jerky? If there is panning or following the bird, is the camera work smooth and steady? Lack of a tripod and jerky camera movements reduce video quality.
- Sharpness and focus continuity: Is the video in sharp focus and is that focus maintained throughout? Soft edges or frequent dips in focus reduce a video’s rating.
- Lighting and exposure: Is the lighting good (not backlit or harshly lit)? And is the exposure set correctly for the lighting (not overexposed or underexposed)?
- Composition and background: Is the composition of the video aesthetically pleasing? Is the background busy or otherwise distracting? Cluttered backgrounds and awkward composition can diminish the aesthetics of a video.
- Watermarks: Downrate 1-4 stars depending on the size and obtrusiveness of the watermark, signature, or other text.
By contrast, when rating videos do not consider the following factors:
- Rarity of the subject and biological content: It’s always exciting to get a video of a rare bird or an unusual behavior, but when it comes to assigning a quality rating to a video, the important things to consider are the technical factors listed above and not the rarity of the bird in the video.
- Length: Longer recordings can be more valuable, but the length of a video shouldn't affect the rating, unless it is extremely short (<5 seconds).
Descriptions of star ratings for video:
- 5 Stars: Excellent quality. High resolution with sharp focus throughout; stable image with good camera work; good lighting; bird is at least fairly large in the frame and not blocked.
- 4 Stars: Very good quality. High resolution with good focus, stable image with good camera work, at least decent lighting, and bird reasonably large in frame. One or two of these factors may be less than ideal and prevent from achieving 5 stars.
- 3 Stars: Decent quality. High or medium resolution with mostly good focus; stable or slightly unstable image; could have some lapses in camera work. Lighting might be less than ideal; bird might be smaller in frame or somewhat obscured. Might have several factors that prevent it from being rated higher.
- 2 Stars: Poor quality. Could be a good image at low resolution, or high resolution but with significant flaws. Image might be unstable or camera work poor, lighting might be severely backlit or poorly exposed. Image might be good but the bird is extremely small in the frame or mostly obscured throughout. May show interesting behavior but be otherwise lower quality. Some may not be worth uploading.
- 1 Star: Very poor quality. Very low resolution or very unstable image; bird may be hard to make out in the frame or have extremely bad exposure. In general should not be uploaded.
Rating sound recordings
The most important factor for rating audio quality is: How loud is the target bird sound compared to the background noise? The rarity of the bird or coolness of the sound should not be factored into the rating.
For bird recordings, the term “background noise” means all sounds other than the target bird: wind, water, cars, planes, boats, insects, other bird species, talkative birding companions, barking dogs, roosters, loud music, and more. It’s a noisy world out there!
An excellent (5-star) recording has a very loud target species and virtually no background noise. A very poor (1-star) recording has so much background noise that it is difficult to even hear the target species. When you listen to a sound recording for rating purposes, pay close attention to how loud the target species is, and then listen carefully to see how much background noise is audible. Good speakers or headphones are best for hearing all the details of a recording, but if you can only listen through laptop speakers, be sure to turn up the volume so that you can hear as much detail (both good and bad) as possible.
Here’s a quick guide to assigning audio quality scores:
- 5 Stars: Very strong target sound with little or no background noise.
- 4 Stars: Strong target sound with limited background noise.
- 3 Stars: Good target sound with moderate background noise.
- 2 Stars: Weak target sound with significant background or handling noise.
- 1 Star: Very weak target sound that is barely audible due to high background or handling noise.
The best way to assign an audio quality score is to listen to a recording while also viewing the associated Macaulay Library spectrogram. A spectrogram is a visual representation of a sound recording that shows different sound frequencies (y-axis) against time (x-axis). And, most importantly for quality rating, a spectrogram also shows the relative loudness of different sounds. Very loud sounds appear black in ML spectrograms, while soft sounds are light gray, and silence is white.
Below are spectrograms of recordings ranging from 5 stars to 1 star.
Note the strong contrast in this spectrogram between the two loud (black) calls and the nearly silent (white) background. Click on the spectrogram to hear the full recording.
This spectrogram also shows a strong contrast between the target sound and the background, but there is some low-level background noise (the gray shading seen in much of the spectrogram), as well as an audible background species.
Note how the overall appearance of this spectrogram is much darker and grayer than the 5-star and 4-star spectrograms. This means that there is more background noise throughout the recording. And, in certain places (around 4 kHz and 8 kHz), there are prominent insect sounds.
The two target sounds in this spectrogram are still easily seen, but the darker gray background indicates that there is even more noise in this recording. In addition, there is a strong insect band visible between 6 and 7 kHz, and a rather loud, nearly continuous background bird species visible at 2 kHz.
In this spectrogram, there is very little contrast between the three descending target sounds (circled) and the noisy gray background.
Listen to the whole recording
Be sure to listen to more than just the first few seconds of a recording before assigning a quality grade. In many cases, the quality will improve later in the recording as a result of the recordist moving closer to the target bird, and such recordings should be rated based on their best section.
If a recording contains a significant amount of handling noise—noise made by the recordist by moving, hitting, or excessively gripping a microphone or smartphone—consider deducting one star from the score that the recording might otherwise receive. Below is an example of a recording with prominent handling noise:
Don’t be fooled by a spectrogram like this that is predominantly white:
This spectrogram might seem like it shows a high-quality recording because the background is entirely white and white backgrounds are an element of 4-star and 5-star recordings. However, high-quality recordings contain both a white background and strong, black target sounds. In this spectrogram, the target sounds are light gray and barely visible. This recording was made at an extremely low recording level, resulting in this washed-out white spectrogram and a target sound that is barely audible. If you see a spectrogram that looks like this and listen to a recording where it is difficult to hear the target sound, give the recording a 1-star or 2-star rating. This also emphasizes the importance of normalizing your recordings before uploading, making it easier to hear and also assess quality of a recording (see our page on preparing audio recordings).
If you see a recording like the spectrogram below that has large portions of audio deleted, give the recording a 1-star or 2-star recording depending on the severity of the editing. In this case, the editing is very extreme, with all sound above 2 kHz removed, so the recording should be given one star:
The Macaulay Library encourages recordists to perform only minimal editing on their recordings, using only a gentle (<250 Hz) filter when necessary. The above recording sounds very unnatural, because so much sound has been removed from it. In addition, valuable acoustic information about the target species has been lost due to the extreme editing. Compare the above recording with this other recording of the same species:
Note the rich harmonic content that is visible (and audible) above 2 kHz, which is where the heavily-edited recording is truncated.