Which birds can be accurately weighed using a gram scale?

The correct answer is that kestrels, peregrines, and gyrs can be accurately weighed using a gram scale. These birds, which are generally smaller to medium-sized raptors, fit well on precision scales and their weights are critical for monitoring health, fitness, and hunting readiness.

Kestrels are small falcons that are easily manageable in terms of weight and handling, while peregrines and gyrfalcons, though larger, are also typically weighed on gram scales for careful monitoring. Accurate weight measurements are essential in falconry to ensure that these birds are in optimal condition, especially during training or before flights.

In contrast, while ospreys, eagles, hawks, owls, vultures, and larger birds of prey may also be weighed, they often require larger scale equipment due to their weight and size. Those options represent birds that may exceed the capacity of standard gram scales, making them less suitable for precise measurement in a typical falconry context. Therefore, the specificity of the answer choice pertaining to kestrels, peregrines, and gyrs highlights the practical application of using gram scales for smaller birds of prey in falconry practices.