The Bee Hummingbird (Mellisuga helenae) is the world’s smallest bird, measuring about two inches long and weighing less than two grams. This minuscule size creates a unique biological challenge, requiring a highly specialized, energy-dense diet to sustain its constant activity. The bird’s survival depends on acquiring fuel to maximize energy intake from the tropical environment.
Primary Fuel Source: Nectar
Nectar is the primary component of the Bee Hummingbird’s diet, serving as the main source of simple carbohydrates for immediate energy. Nectar provides a high-octane sugar solution composed predominantly of sucrose, glucose, and fructose. The bird seeks a specific sugar concentration, ideally between 15 and 30 percent, to maximize energy return during feeding.
The preferred flowers are small, tubular, and display bright colors like red or orange, making them easily visible. These blossoms often lack a landing perch, requiring the hummingbird to hover while drinking. This reduces competition from other, heavier pollinators. The Bee Hummingbird seeks out the nectar of plants such as Solandra grandiflora.
Essential Protein: Insects and Arthropods
While nectar supplies carbohydrates, it is deficient in protein, fats, vitamins, and minerals required for growth and tissue repair. To compensate, the Bee Hummingbird supplements its sugar intake with insects and small arachnids. This protein is necessary for maintaining muscle mass, developing new feathers, and producing eggs during the breeding season.
The tiny prey consumed includes soft-bodied arthropods such as small flies, gnats, aphids, and spiders. The birds employ two main strategies for acquiring these creatures throughout the day. They use hawking, catching insects in mid-air during rapid flights. Alternatively, they use gleaning, picking spiders or insects directly off leaves, branches, or spiderwebs.
Specialized Feeding Techniques
The Bee Hummingbird has evolved specialized mechanisms to efficiently extract nectar while hovering. Its wings beat at a high rate, creating the lift and precise maneuverability needed to maintain a stable position. This ability allows the bird to access nectar in deep floral tubes unreachable for most other birds.
The most distinctive feeding tool is its long, forked tongue, which is not used like a straw. The tongue is extended and retracted in a rapid lapping motion, up to 20 times per second. The two tips are lined with tiny, hair-like structures called lamellae. These lamellae curl inward when submerged, trapping the nectar through surface tension and capillary action. When the tongue is retracted, the bill closes slightly to squeeze the nectar into the digestive tract.
Fueling a Tiny Engine: Metabolic Needs
The tiny body size and constant activity of the Bee Hummingbird result in one of the highest mass-specific metabolic rates of any warm-blooded animal. This incredibly fast metabolism necessitates a prodigious food intake to maintain a stable body temperature and power rapid flight. To meet this demand, the bird must consume a staggering quantity of food, taking in up to half its body weight in pure sugar every day.
The bird must feed almost constantly throughout the day, often visiting hundreds of flowers to sustain energy reserves. When active foraging is not possible, such as during cold nighttime hours, the Bee Hummingbird employs a survival strategy called torpor. During torpor, the bird dramatically reduces its metabolic rate, sometimes to one-fifteenth of its normal rate, and lowers its body temperature. This temporary state conserves energy and prevents the bird from starving during periods of insufficient food.