Bird’s Foot Trefoil

Bird’s-foot trefoil (Lotus corniculatus) is a resilient legume, a member of the Pea Family.

It Has Over 130 Nicknames: Because the petals shift from yellow to orange/red as they age, it is famously known as "Eggs and Bacon". Other historical names include "Granny's toenails," "Cat's claws," and even "Lady's shoes-and-stockings".

It's a "Trefoil" with 5 Leaves: While often called a trefoil (implying three leaflets like clover), it actually has five. Three are clustered at the top, and two more are tucked down near the stem.

It Can Defend Itself with Cyanide: As a self-defense mechanism, the plant contains cyanogenic glycosides, which release hydrogen cyanide if the leaves are damaged or chewed by herbivores.

It Needs Heavy Pollinators: The flower is built like a little slipper. It requires heavy insects, like bumblebees, to force the petals open and trigger pollen release, ensuring only the most capable pollinators carry its genetic material. 

A Magnet for Butterflies: It is the primary caterpillar food-plant for several striking and endangered species, including the Common Blue and the Silver-studded Blue.

Seed Pods Look Like Claws: The seed pods grow in star-shaped clusters that look distinctly like the clawed foot of a bird—which is exactly how it got its primary common name.

Bird's-foot trefoil (Lotus corniculatus) is a robust legume with complex, bilaterally symmetrical flowers. Because of this morphology, the plant relies almost exclusively on strong insects like bees to force open the petals and access nectar, which triggers pollen transfer.

Primary pollinators include:

Bumblebees (e.g., the Red-tailed and Garden bumblebees) are the most effective and common pollinators.

Solitary bees (e.g., Pine-wood, Mountain, and Wall mason bees), which are highly specialized to forage on legume pollen.

Honeybees. Wasps. 

While other insects like butterflies (e.g., Common Blue, Wood White) and moths (e.g., Six-spot Burnet) visit the flowers, they are primarily looking for nectar and do not play a major role in pollination. However, the plant is a critical food source for their caterpillars.