How are falconiforms divided into the families Accipitridae and Falconidae?

The classification of birds within the order Falconiformes—often referred to as diurnal raptors—distinguishes between the families Accipitridae and Falconidae based on several morphological, behavioral, and developmental characteristics.12

Key Distinctions

• Anatomy and Appearance: While both families share features such as hooked beaks, powerful feet with talons, and sexual dimorphism, they differ in specific traits. Falconidae are characterized by a toothed beak, sharply pointed wings, and a noncentrifugal wing molt. In contrast, Accipitridae generally possess strong, hooked talons and exhibit different molt sequences.12
• Eggshell Characteristics: A primary diagnostic tool for classification is the color of the inside surface of the eggshell. The eggs of Accipitridae have a green inner surface, whereas those of Falconidae are reddish.12
• Behavior and Nesting: Members of the Accipitridae family typically build their own nests. Conversely, most members of the Falconidae family do not build nests, with the exception of caracaras. Additionally, their waste-disposal behaviors differ: Accipitridae squirt their droppings, while in Falconidae, droppings fall directly below the perch.2

While these groups are traditionally placed together in the order Falconiformes, some modern taxonomies separate them, placing Accipitridae into the order Accipitriformes.3