⚖️ Weight Management Math · 6 min
Units, and why falconry uses two of them
Why this matters
Half of falconry literature is written in ounces and the other half in grams, sometimes in the same paragraph. The regulation itself gives the scale requirement in both. You need to move between them without thinking.
By the end of this lesson you will be able to
- Convert between ounces, pounds, grams and kilograms
- State the regulatory minimum scale resolution in both units
- Judge whether a given scale is adequate for a given bird
The conversions
| From | To | Multiply by |
|---|---|---|
| ounces (oz) | grams (g) | 28.35 |
| grams | ounces | divide by 28.35 |
| pounds (lb) | grams | 454 |
| pounds | ounces | 16 |
| kilograms (kg) | grams | 1,000 |
Two anchors worth memorising outright: 1 oz = 28.35 g and 1 lb = 454 g. Everything else falls out of those.
The regulatory floor
173.6(a)(4)(vi) requires a scale graduated in increments no coarser than one half ounce, which the regulation itself glosses as 15 grams. Half an ounce is actually 14.2 grams, so the regulation rounds up slightly. Either way, that is the legal floor, and it is a poor working target.
Why 15 grams is not good enough for a Kestrel
A female American Kestrel might weigh 120 g. Fifteen grams is 12.5% of her body weight: an entire flying range and then some, invisible inside one graduation. On a 1,200 g red-tail, 15 g is 1.25%, which is coarse but survivable. This is why the manual says preferably grams and why every kestrel falconer uses a gram scale reading to 1 g.
Worked examples
An average male red-tail weighs 34 ounces. What is that in grams?
34 × 28.35 = 964 g.
A female red-tail at the top of the published range weighs 70 ounces. In pounds and grams?
70 ÷ 16 = 4.4 lb. 70 × 28.35 = 1,985 g, just under 2 kg.
Your scale reads 1,143 g. What is that in ounces?
1,143 ÷ 28.35 = 40.3 oz, so a bird in the overlap zone: a heavy male or a light female.
This lesson is part of the NY Falconry Exam course. Open it in the course to answer the retrieval checks that go with it, track what you have read, and quiz the whole unit. Lessons, quizzes and the glossary are free.