Falconry · Falqora
What is flying weight in falconry and how do you track it
Flying weight is the range at which a particular falcon is keen to fly to the falconer and hunt while staying strong and healthy. It differs from bird to bird and is not set by a formula. Falconers find it by weighing every day on an accurate scale, with an empty crop, and writing each reading down.
What flying weight means
Falconers talk about a bird's flying weight, or flight weight, as the working range in which she is alert, responsive and ready to hunt. The International Association for Falconry and Conservation of Birds of Prey (IAF) describes trained raptors as athletes: their body fat has to be reduced, but not depleted totally, and their muscles built up. Its welfare guidelines, approved by the IAF Assembly of Delegates in Doha in January 2014, are explicit that the motivation involved is ordinary appetite and has nothing to do with starvation. A starving bird, the guidelines point out, would lose the ability to hunt efficiently.
The falconry examination manual published by the New York State Department of Environmental Conservation uses the words keen and sharp-set for a bird in that state: hungry, alert and ready. The same manual is clear that flight weight is not a fixed number. It may vary with temperature, and the manual lists a long set of other influences on a bird's weight and condition.
So there is no single correct figure for a species. Two falcons of the same species and sex can fly well at different weights, and one bird's working weight can shift over a season. What an experienced falconer carries around is a band for one bird, built from that bird's own records.
Why falconers weigh every day
The New York manual puts the question directly to trainees: how often should a novice weigh a bird? The answer it gives is once each day. It calls a scale absolutely essential and says daily weighing during the flying season is mandatory. Another of its questions names weighing as the most objective and reliable way for a beginner to judge condition, ahead of looking at the feathers, feeling the keel or checking the brightness of the eyes.
The IAF guidelines arrive at the same habit from the welfare side. They say it is very useful to monitor the weight daily with proper scales and to document it in written form, because weight gives a good indication of the bird's appetite and general health. They also add a caution that matters: body weight is not the main indicator of hunting motivation, and experienced falconers watch the bird's behaviour as well as the number.
How to get a reading you can trust
In the chapter on the management of raptors in Clinical Avian Medicine, the veterinarian Jaime Samour sets out the practical rules. A trained, hooded raptor can usually be persuaded to stand on a scale fitted with a perch, and commercially available electronic scales with perching surfaces are recommended. The scale's accuracy should be within plus or minus 1 percent of the bird's body weight. For a falcon of 1,000 g, that means a reading you can trust to within 10 g.
Samour adds two details that are easy to skip. With falconry birds, the weight of the accessories, meaning the hood, jesses and bells, has to be taken into account, so weigh in the same equipment each time or subtract it. And he calls it of paramount importance that the bird is weighed with an empty crop. A reading taken after a meal mostly tells you about the meal.
Some regulators also set a minimum. New York's falconry regulations, printed in the state's manual, require a reliable scale or balance graduated in increments of not more than half an ounce (15 grams). That is a legal floor in one state rather than a target; the scale in Samour's own illustration of a saker falcon being weighed reads to 1 g.
What moves the number
The New York manual lists what affects a bird's weight and condition: the type of food, the quality of food, the weather and especially temperature, disease, season, barometric pressure, the amount of exercise, the species, and the individual bird's metabolism and ability to assimilate food. A single heavy or light morning is rarely a story on its own. A run of readings is.
The Merck Veterinary Manual's page on nutrition in raptors says captive raptors should be weighed regularly and food volume adjusted as needed to prevent both emaciation and obesity. As a broad scale, it gives daily intake of about 15 percent of body weight for raptors of 200 to 800 g and 6 to 10 percent for raptors of 800 to 7,000 g. Those figures span many species and are not a ration for any one bird. Where weighing is not possible, the same page describes checking the keel, the breastbone: if it feels sharp the bird is emaciated, and if it is covered in palpable fat the bird is obese.
Season matters too. The New York manual recommends that falconry birds kept through the moult be held in high condition in a stress-free setting to support feather growth, and it notes that birds generally lose weight more slowly in warm weather, which makes weight management harder in the heat.
Common weight-tracking mistakes
Weighing after food. Samour's rule is an empty crop. A reading taken after the bird has eaten measures the meal as much as the falcon, and it will sit oddly in the record for days.
Changing the setup. Weighing with the hood on one day and off the next, or with different jesses or bells, moves the number without the bird changing at all. Pick one setup and keep it.
Trusting the number over the bird. The IAF guidelines say weight is not the main indicator of hunting motivation. Behaviour belongs in the record too. Bringing weight down fast is the other trap: in its question on manning a new bird, the New York manual rejects starving weight off quickly in favour of using food to encourage a response, and elsewhere it says plainly never to starve your bird.
Not writing it down. A number you remember is not a record. The New York manual's advice is to use a scale daily and keep a log to monitor patterns, and the IAF asks for the weight to be documented in written form.
Keeping the log
A useful weight log holds the date, the time, the reading, the equipment the bird had on, and a line on how she flew, with feeding and training written beside it so the whole day can be read together. A notebook works, and so does a spreadsheet. What the IAF and the New York manual agree on is that it is kept every day.
If you would rather keep that record on your phone, Falqora is a falconry journal that plots each morning's weight on a season curve against a hunting weight band you set yourself, with feeding and training entries marked on the same dates. It does not suggest a weight or a ration; the judgement stays with you.
This guide is general information, not veterinary advice. A flying weight is worked out for one bird by its falconer. If your falcon loses weight unexpectedly, stops eating or seems unwell, contact an avian veterinarian.
Frequently asked questions
How accurate does a falconry scale need to be?
The veterinarian Jaime Samour, writing in Clinical Avian Medicine, says accuracy should be within plus or minus 1 percent of the bird's body weight, about 10 g for a 1,000 g falcon. New York's regulations set a minimum graduation of half an ounce (15 grams), and Samour's own example is an electronic scale accurate to 1 g.
Should I weigh my falcon before or after feeding?
Before. Samour calls it of paramount importance that a bird is weighed with an empty crop, and the hood, jesses and bells it wears have to be accounted for each time.
Does flying weight change with the weather?
It can. The New York State falconry manual says flight weight may vary with temperature and that birds generally lose weight more slowly in warm weather.
Is weight enough to tell if my falcon is ready to fly?
Not on its own. The New York manual calls daily weighing the most objective check for a beginner, but the IAF guidelines say weight is not the main indicator of hunting motivation and that experienced falconers watch behaviour as well.
What if I cannot weigh my bird?
The Merck Veterinary Manual describes feeling the keel: sharp suggests the bird is emaciated, covered in palpable fat suggests obesity. It is a rough check, and a proper scale is still the standard.