How do diving petrels differ from long-winged procellariiform birds?

Diving petrels (family Pelecanoididae) differ significantly from other long-winged procellariiform birds in their physical structure and locomotion. While most procellariiforms are characterized by long, narrow wings adapted for efficient, fixed-wing gliding, diving petrels possess short wings and heavy bodies.12

These physical differences reflect their distinct ecological niches:

• Locomotion: Unlike their long-winged relatives that rely on gliding, diving petrels use their wings for propulsion underwater, a behavior that allows them to pursue prey beneath the surface.13
• Appearance: Diving petrels are small, stocky, black-and-white birds. They exhibit a classic example of convergent evolution, as they more closely resemble the auks of the Northern Hemisphere than they do other members of their own order.145
• Beak Shape: While many procellariiforms have bills adapted for surface feeding or scavenging, diving petrels have relatively short, broad bills.26

Despite these differences, all members of the order Procellariiformes share key taxonomic features, including tubular nostrils, webbed feet, and a distinct musky odor.47