Some hints on making good, well-documented bird recordings
Making recordings is easy, but making great recordings is not. The following are some hints, most of which we've learned through personal experience. If you have additional hints, let us know!
If you can afford it, get good equipment! The options are bewildering and constantly changing, and for this reason you might prefer to go with tried and true equipment packages recommended specifically for bird recording, such as those on the http://www.stithrecording.com/ website. Obviously, you get what you pay for and a one-time investment is likely preferable to many expensive field trips using poor equipment that cannot produce good recordings.
Use a windscreen appropriate to the local conditions; if very windy, your microphone will need extra wind protection beyond the affordable foam windscreens. Even the best windscreens don’t solve the problem entirely, but in windy situations you can often improve results by placing the mike close to or on the ground, using your body or vehicle to block the wind, and/or pointing the mic either directly into or directly away from the direction of the wind. Make many more recordings of a given bird than you normally would in windy conditions because some are likely to be ruined by wind shear.
- Mechanical noise:
Avoid recording near highways, busy airports, or ferry terminals etc. Distant road noise is low-frequency and so can be edited out, but a nearby passing truck will ruin a recording.
- Running water:
Water noise is one of the most difficult problems a bird recordist will encounter, especially since many birds are attracted to, or only found, near running water. If you must record near running water, try pointing the mic at different angles, especially higher than normal, and try different input levels. The more recordings you make with different settings and from different angles, the more likely you will end up with something usable.
- Recordist noise:
Avoid talking, moving, loud breathing, coughing, etc. while recording. Hold the mic, cord, and recorder absolutely still whenever possible. If you must move while recording to capture a target sound in a different direction, try to swivel smoothly with your legs rather than your arms. Always use a good quality shockmount and handle. Try to wear fabrics that don’t rustle. If you must talk or move, time this for breaks between the bird’s vocalizing, if possible. If photographing the bird you are recording (which we strongly encourage!), you’ll probably have to edit your recordings more often, and frequently camera clicks and/or stalking noise will obscure segments of the recording. One way to minimize this is, if a stationary singing bird is at a good distance for recording, to put the recorder down while recording with the mic pointed at the bird, then to stalk it with the camera from a different direction or position.
- Companion noise:
- Go it alone, or instruct companions on keeping quiet. If walking, ask companions to stop when you stop, avoid rustling, zipping, undoing Velcro fasteners, etc. Even in a relatively noisy group or trailed by children, and you can’t ask them to be quiet, it is still possible to make adequate or even good recordings some of the time, or at least to edit out much of the speech and other human noise; make more than you think you need! This is especially true if you are recording high-frequency bird sounds. Distant human speech or singing is confined to low frequencies and is easily edited out.
To avoid later confusion, limit the amount of playback and imitation, and clearly note these events in your narration (ideally right before or after).
- Continuous recording:
If time at a particular site is at a premium, consider recording continuously when in good habitat, at prime time, or when awaiting an elusive species that vocalizes unpredictably. While this results in numerous bad or empty recordings (which can simply be discarded), you may get some good ones that you wouldn’t have if you had waited until the bird vocalized before starting to record (which often means having to wait several sec before you can record). For unusual species/vocalizations that are most likely to result from a bird being flushed, your only option may be to record while walking, and immediately stopping when the bird is detected. Note that if battery life is an issue the continuous recording strategy may not be recommended.
- Input levels:
Continuously monitor the input, ideally using headphones. If you don’t use headphones, make it a habit to look at the input level indicator lights frequently and adjust levels as necessary. A badly clipped (over peak) recording is essentially ruined, as this problem cannot be edited out. Under most conditions the input level should not be at its highest setting unless you are trying for a quiet or distant bird.
- Number and length of recordings:
Generally the safest practice is to make many more recordings than you think you need when a good opportunity presents. Chances are that many of them will be suboptimal for one reason or another. Particularly in the case of rare species or unusual vocalizations, it’s best not to assume you’ve got good recordings and just walk away—-review them before leaving the bird or area in case you need to make more! Also, make longer, complete recordings whenever possible rather than just capturing a few notes and walking away. Strophe length, pause length, and/or repetition patterns are often key to a species’ identity. That said, it’s easier in, for example, Raven (Cornell Lab of Ornithology Bioacoustics Program), the program we use, to work with moderate length (5 min or less) recordings than really long ones. A few medium-length recordings also take less cataloguing effort later on than many very short ones, as well.
Many recorders use a lot of batteries, so whenever possible use rechargeable ones, and try to get a fairly fast charger but one that that won’t blow out your power converter in dicey current. If using a vehicle, carry one or more car chargers for your battery charger. Make sure you have plenty of options! Chances are some of them won’t work. In most developing countries, non-rechargeable battery quality is low, and locally available battery chargers for rechargeable batteries may take many hours, so be sure to bring as many as you need with you if possible.
- Focusing on a single species:
While it can be valuable to obtain recordings of the dawn chorus and mixed species-flocks, such recordings are typically not the most useful ones as representatives of a single species, or it may be difficult to determine which bird is responsible for which sound. Whenever possible (unless dealing with serious wind or water noise), focus in on a single vocalizing bird, pointing the mic directly at the target as one would a shotgun, and track the moving bird by swiveling at the legs rather than the arms. With directional mics, the more on-axis your mic is, the clearer the recording. Concentrating recording effort during times when or places where fewer species are singing is likely to yield better results than in peak situations.
Before going out in the field, check that your recorder is set for the correct date and time, including time zone. This is important not only to provide accurate time-of-day data, but also to coordinate with photographs you may have taken (in which case you also need to ensure that your camera and recorder are both set for the correct date and time).
- Memory cards:
Frequently download memory cards, safeguard the full ones in their plastic cases, and back up your recordings. Keep the full ones in one zipped compartment and the empty ones in another. Don’t let them get wet, especially in salt water! Make sure you have plenty of cards, and don’t reuse any that malfunction.
- Data format:
We recommend using WAV format, 24-bit, 44.1 kHz or higher when possible. Files higher than 44.1 kHz will take up a lot of space and may be hard to work with later, e.g. in Raven. While MP3 format takes up little space, your recordings will have lost a lot of information you can just as easily keep, and you can’t get it back later. And, it’s easy to make MP3s of your WAV files later.
One of the most important, and most often neglected, aspects of making good recordings is documenting them properly (see downloadable “AVoCet Recordings Documentation” file). We recommend narrating each recording set at the start with date, time, location, GPS coordinates, elevation, habitat, position of the sun (if near dawn or dusk, at night, or in a situation where the sun doesn’t hit the vegetation until long after dawn), and weather (% cloud cover; approximate temperate, specifying scale; precipitation if any; wind strength), and recordist (if any possibility for confusion. Any changes in the above information should be updated as necessary. After each known or important recording or set, ideal narration would indicate:
A typical recording will not have all this information in the narration, nor is it necessarily important each time, but the more data with your recording, the more scientifically valuable the recordings!
- the species name;
- whether the bird was seen or not, if so how well, and if a difficult ID what characters were used to distinguish it;
- whether the bird was actually seen making the sound in question;
- if any possibility of confusion over which sound is meant an imitation of the sound would be given;
- behavioral information;
- approximate numbers of individuals seen and/or recorded;
- sex, other plumage category and/or age, and how determined;
- whether the bird recorded was photographed and if so the photo number(s);
- whether the individual recorded was the same as in previous cuts;
- whether playback, imitation, or other arousal sounds were used;
- other birds, mammals etc. seen that might have made or elicited the sounds recorded;
- any other relevant information.
When narrating a recording, ensure that the input level is appropriate for speech; this is likely to entail putting the machine on the internal mic setting or simply turning down the input. Speak directly, plainly, and slowly into the mic. Don’t try to narrate while walking, in strong wind, or when heavy trucks are passing. If your narration is lost your recording is likely to lose scientific value. Check that your narration is intelligible, and remember to turn the input back up or switch back to external mic as necessary. Some individuals may prefer to take notes in a field notebook, and it is a good policy to at least note down times, recording numbers, etc. of especially important recordings in a notebook in any case.