The American white pelican is a large waterbird found in North America. With its striking white plumage and huge bill, the American white pelican is a distinctive sight as it soars across the sky or floats on the water. Though majestic to behold, the size of these birds requires them to consume a tremendous amount of food each day to maintain their energy needs. In this article, we will explore how much food American white pelicans eat on a daily basis and what factors influence their impressive consumption.
Average Food Consumption
An adult American white pelican needs to eat around 1.5-2.5 kg or 3.3-5.5 lbs of food per day on average. However, this amount can vary based on the pelican’s size, age, time of year, and food availability.
On an annual basis, each American white pelican consumes approximately 680-850 kg or 1,500-1,875 lbs of food. This substantial intake provides the energy and nutrients needed to support the pelican’s large body mass and active lifestyle.
What Do They Eat?
The diet of American white pelicans consists mainly of fish, but they also eat some amphibians and crustaceans. Common fish consumed include carp, suckers, bullheads, sunfish, and perch. Crayfish are another frequent item on the menu.
Pelicans have specialized pouches built into their bills that can hold up to 3 gallons of water and food. Working together, groups of pelicans can corral fish into shallower water to more easily scoop them up in their pouches. The pouches contract to push out excess water before swallowing their catch.
Factors Influencing Food Intake
Several key factors determine how much an American white pelican needs to eat each day:
Body size
Larger pelicans require more food than smaller ones. Some of the biggest males can reach weights over 10 kg or 22 lbs. Meeting the energy demands of these larger bodies necessitates greater consumption.
Thermoregulation
During cold weather, American white pelicans have higher metabolic rates to produce body heat and maintain their temperatures. This increased metabolism requires additional calories, so food intake goes up in winter.
Breeding season
Adult pelicans need extra nutrition during breeding season to support egg production and chick rearing. Their food intake increases up to 50% above non-breeding levels at this time of year.
Molting
Molting, or renewing feathers, is an energy-intensive process. American white pelicans eat more while replacing their feathers to meet these additional energy requirements.
Age
Younger pelicans need more food relative to their body size compared to adults. Their high-metabolism supports rapid growth and development.
Activity level
The more active a pelican is during the day through flying, diving, and foraging, the more calories it burns and must consume through food. Inactive pelicans eat less.
Food availability
When food is scarce, pelicans may get by on less. But under normal conditions, they eat as much as available to meet their dietary requirements. Periods of unusual plenty also allow them to eat more.
Eating Habits
To meet their hefty dietary demands, American white pelicans display some fascinating feeding behaviors and adaptations:
Social feeding
Pelicans often forage together in groups, working cooperatively to herd fish into shallower waters for easier feeding. They may even form a line and beat their wings to move fish toward the shore.
Gulping ability
Their expandable throat pouches allow pelicans to gulp down large amounts of food and water. Once contracting the pouch, excess water flows out before swallowing.
Daily routines
American white pelicans usually feed most actively in the early morning and evening when fish are nearer the water’s surface. They may rest or loaf during midday before resuming foraging later.
Reusable pouches
The skin and muscles of their throat pouches allow pelicans to empty then refill them multiple times during a single foraging trip. This repeat use enables them to catch more food before stopping to digest.
Food storage
Sometimes pelicans may store extra food in their pouches to eat later. This helps ensure they meet their nutritional needs even if foraging becomes more difficult.
Digestion and Metabolism
To process all the food they consume, American white pelicans have some unique digestive adaptations:
Multi-chambered stomach
Their stomach has a compartmentalized design, allowing pelicans to store and digest fish while continuing to feed.
High metabolic rate
A pelican’s metabolism runs over twice as fast as a similar-sized mammal’s. This rapid rate provides the energy these large, active birds require.
Food retention
Food can remain in a pelican’s stomach for over 48 hours while being slowly digested. Their digestion is up to three times slower than many birds.
Low energy density diet
Fish and other aquatic prey tend to be low in calories compared to many bird foods. More intake is required to meet energy needs from this less energy-dense diet.
Salt gland
A specialized nasal gland removes excess salt from the bloodstream that pelicans ingest while feeding on fish. The concentrated brine then drains off through the bill.
Young Pelican Diet
Chicks and juvenile pelicans have somewhat different nutritional needs and feeding behaviors:
Regurgitation feeding
For the first week or two, parents regurgitate partially digested food from their pouches to feed newly hatched chicks.
Fish and aquatic prey
Once able to feed independently, young pelicans eat similar foods to adults but can swallow smaller items like minnows and tadpoles.
Frequent small meals
Chicks may eat up to 20 times per day but consume less per meal than adult birds. Their smaller stomachs require more frequent feedings.
Greater relative consumption
Baby pelicans may eat over double their own body weight daily to support rapid growth and development. Their food intake relative to size is much higher than adults.
Extended parental care
Young pelicans rely on their parents for additional weeks or months after fledging. The parents continue supplementing their offspring’s diet after leaving the nest.
Unique Adaptations
Over the course of evolution, American white pelicans have developed some remarkable adaptations to their fish-based diet and immense daily intake requirements:
Large strong bill
The long bill with its hook at the end is ideally suited for catching slippery fish. It also serves as an efficient scoop.
Distensible pouch
The elastic pouch holds huge volumes of food and water until the pelican is ready to swallow. It can expand to over three gallons.
Webbed feet
Broad webbed feet propel the pelican while swimming and maneuvering for fish capture. The webbing provides agility and speed in water.
Keen eyesight
Excellent long-distance vision allows pelicans to spot fish concentrations while flying at heights over 70 meters or 230 feet.
Light skeleton
Despite their large size, a pelican’s bones are highly pneumatized and light-weight. This reduces energy needed for flight while foraging.
Teamwork
By working together and using coordinated feeding strategies, groups of pelicans can maximize their fish-catching efficiency and get more food collectively.
Conclusion
The American white pelican is a predator supremely adapted for devouring fish. With its huge throat pouch, hefty bill, keen sight, cooperative foraging, and other specialized traits, this bird consumes an average of 1.5-2.5 kg or 3.3-5.5 lbs daily. Their high-volume diet consisting mainly of fish provides the energy these massive waterbirds need to fly, float, dive, and rear their chicks. Though requiring impressive quantities of food, the pelican’s unique digestive and foraging adaptations allow it to thrive across North America’s lakes and rivers. After learning about their tremendous daily intake requirements, it’s clear the American white pelican has earned its status as North America’s largest piscivorous bird.
