Hawks occasionally prey on toads, but this interaction is not common in their feeding habits. The consumption of toads is limited by the potent chemical defenses these amphibians have developed for protection. Hawks that engage with this prey must employ specific, learned behaviors to safely bypass the toad’s toxic skin.
Hawk Predation on Toads
Hawk predation on toads is generally opportunistic and tends to occur when more traditional prey is scarce or locally less abundant. Certain hawk species, particularly those with a wider range of acceptable prey, are more frequently observed engaging in this behavior. For instance, the Broad-winged Hawk (Buteo platypterus) is known to include frogs and other amphibians in its diet, especially during the non-breeding season.
Observations have recorded species like the Red-shouldered Hawk (Buteo lineatus) capturing the Giant Toad (Rhinella marina), a large invasive species in some regions. Swainson’s Hawks (Buteo swainsoni) have also been documented preying on spadefoot toads, often hunting them from the water’s surface during breeding choruses. The frequency of toad consumption is closely linked to the seasonal availability of the amphibians, such as during mass breeding events when toads are concentrated targets.
The Chemical Barrier: Understanding Toad Toxicity
The primary deterrent against toad consumption is the defensive secretion known as bufotoxin, produced by the toad’s skin. This substance is concentrated in the large parotoid glands, which are prominent raised structures located behind the amphibian’s eyes. When a toad is stressed or attacked, it can exude this toxin from these glands onto its skin surface.
Bufotoxin is a cocktail of chemical agents, including bufadienolides and bufotenine, which act on the predator’s physiological systems. Bufadienolides are cardiac glycosides that interfere with heart function, causing severe arrhythmias and cardiac arrest in many animals that ingest them. Other components, such as the neurotoxic bufotenine, can affect the central nervous system, leading to paralysis or disorientation. The potency and specific composition of the toxin varies significantly depending on the toad species, making this prey a considerable risk for any predator.
Specialized Feeding Behaviors
Hawks that successfully consume toxic toads rely on specialized behavioral adaptations to circumvent the chemical barrier. The most widely recognized technique is the careful avoidance or removal of the toxic skin and glands before ingestion. Raptors often begin by manipulating the toad with their beak and talons, aiming to bypass the parotoid glands entirely.
Some hawk species have been observed to perform a “skinning” action, where they use their sharp beak to peel the skin away from the body, similar to how they might prepare a snake or frog. One documented observation of a Red-shouldered Hawk involved the raptor rolling the Giant Toad onto its back, suggesting an attempt to keep the toad’s toxic dorsal surface away from its mouth. By consuming only the non-toxic internal muscles and organs, or by focusing on the less-toxic limbs, the hawk can access the nutritional value of the prey. These precise actions are likely learned behaviors, where the predator links the noxious taste or immediate negative effects of the toxin to the toad’s external features.
General Hawk Diet and Prey Diversity
The typical hawk diet is dominated by a diverse range of non-toxic prey, which forms the bulk of their energy intake. Small mammals are a staple for many North American raptors, including voles, mice, ground squirrels, and rabbits. They are also adept hunters of various reptiles, such as lizards and snakes, which they often prepare by skinning before eating.
The hawk’s diet includes insects, such as grasshoppers and beetles, especially for smaller hawk species or during specific seasons. Hawks are also known to prey on smaller birds, including doves and starlings, using their speed and agility to capture them in flight or on the ground. The occasional consumption of toads is an opportunistic addition to a diet that primarily focuses on safer, more calorically dense prey items.