Raptor Weight & Flight Log

A raptor's "flying weight" is the precise weight at which it is fit, responsive, and motivated to hunt. Too heavy, and the bird becomes sluggish and unresponsive to the falconer. Too light, and it risks health problems, weakness, or even starvation. Most falconers weigh their birds daily with a digital gram scale and adjust food intake to maintain the ideal flying weight. A Peregrine Falcon, for example, may have a flying weight of 750–950g for males and 950–1300g for females, depending on the individual.

In falconry terminology, the female raptor is called a falcon, while the male is called a tiercel (or tercel). The term "tiercel" comes from the Latin word tertius, meaning "one-third," because male raptors are typically about one-third smaller than females. This size difference is called sexual dimorphism and is especially pronounced in falcons and accipiters. Understanding your bird's gender helps set appropriate weight targets.

Daily weighing is highly recommended during the hunting season and active training periods. Most experienced falconers weigh their birds at the same time each day—typically in the early morning before feeding. Consistent daily weight tracking helps you detect trends early, adjust food rations precisely, and ensure your raptor is always at its optimal flying weight. During the molt or off-season, weighing can be reduced to 2–3 times per week.

Creance training is a fundamental technique where the raptor is attached to a long, lightweight line (typically 30–100 meters) during early flight training. This allows the bird to fly and be recalled safely without the risk of escape. The creance gives the falconer control while the bird builds flight fitness, learns recall commands, and develops confidence. It's an essential step before progressing to fully free flight.

Ideal conditions vary by species, but generally: clear to partly cloudy skies with light to moderate winds (5–15 mph) are excellent. Strong winds can make flight difficult and dangerous, especially for smaller raptors. Rain dampens feathers and reduces a bird's willingness to fly. Extreme heat can cause overheating during exertion. Many falconers prefer early morning or late afternoon flights when temperatures are moderate and thermals are less intense. Always monitor your bird's behavior and adjust based on its fitness level and species characteristics.

A raptor at its correct flying weight will be alert, responsive, and eager to fly. Signs include: immediate attention when you enter the mews, quick response to the lure or recall, strong and sustained flight, and a healthy appetite. If the bird is too heavy, it may be slow to respond, distracted, or refuse to fly. If too light, it may appear lethargic, have sunken eyes, or show keel prominence. Every bird is unique—track weight trends alongside behavioral observations to find your raptor's individual "sweet spot."

Grams (g) are the standard unit used by falconers worldwide for precision. Digital gram scales are inexpensive and accurate to ±1g. For larger raptors like Golden Eagles (3–6 kg), some falconers also track weight in ounces (oz) or pounds (lb). This tool supports both grams and ounces—toggle between them using the unit button next to the weight input. 1 ounce ≈ 28.35 grams. For the most accurate tracking, we recommend sticking with grams.

Yes! Click the "Export CSV" button to download your complete flight log as a CSV file. This format is compatible with Excel, Google Sheets, and most spreadsheet applications. Regular exports are recommended for long-term record-keeping, veterinary consultations, and breeding documentation. All data is also saved automatically in your browser's local storage, so it persists between visits.