Puffins are seabirds that are known for their colorful beaks. They are found across the northern hemisphere and spend most of their lives out at sea, only coming to land during breeding season. Puffins have a diverse diet that consists mainly of small fish, but they also eat other sea creatures like crustaceans, squid, and marine invertebrates. Understanding what puffins eat is important for preserving their populations and marine ecosystems.
Small fish are the main part of a puffin’s diet
Small schooling fish like herring, sand lance, and capelin make up 60-80% of a puffin’s diet. Puffins are well adapted to catch these speedy fish. They have a laterally compressed beak that allows them to hold several fish at once. Puffins flap their wings up to 400 beats per minute underwater to propel themselves fast enough to catch darting fish. Their excellent underwater vision allows them to target fish efficiently.
Puffins mainly catch small fish that measure 2-15 cm long. Small fish are abundant in puffin feeding grounds and provide a reliable, energy-dense food source. By primarily targeting small schooling fish, puffins can maximize their caloric intake during challenging hunting conditions.
The types of small fish puffins eat depends on location and availability:
- In the North Atlantic, puffins rely heavily on sand lance and herring
- In Iceland, capelin is a key prey item
- In Alaska, puffins eat juvenile salmon, herring, and sand lance
- In the North Pacific, they eat Japanese anchovy, Pacific saury, and smelt
Regardless of location, small oily fish almost always dominate a puffin’s diet during the breeding season when they need extra energy to raise chicks. Their body mass increases by up to 40% and they end up eating 60 to 120 small fish per day. Puffin chicks grow rapidly and require high-calorie oily fish fed to them several times a day in order to survive.
Crustaceans and mollusks provide variety
Although small fish comprise the bulk of their diet, puffins also supplement their diet with other marine creatures like crustaceans, squid, and mollusks. These prey items add variety and provide different nutrients.
Some common crustaceans eaten by puffins include:
- Krill – abundant tiny shrimp eaten during winter
- Crab larvae
- Copepods
- Isopods
- Amphipods like sand hoppers
Mollusks such as mussels, cockles, limpets, and periwinkles are also preyed upon opportunistically by puffins. Their hard shells require vigorous shaking and beating against the roof of puffins’ mouths to break open.
The most common mollusks eaten include:
- Blue mussels
- Common periwinkles
- Common cockles
Squid and other cephalopods are taken when available, providing puffins with an alternate source of protein.
By varying their diet with these marine invertebrates, puffins get nutrients like amino acids, minerals, and omega-3s to complement the fish they eat. This dietary flexibility allows them to thrive in changing marine environments.
Diet depends on location and season
What puffins eat varies based on the time of year and colony location. Their ability to exploit seasonal food resources helps them survive challenging conditions.
Breeding vs nonbreeding season
During the breeding season (April to August), puffins eat the most fish – up to 60-120 fish per day. This fuels the energetic demands of courtship, incubating eggs, and provisioning chicks.
In the nonbreeding season, their diet is more varied including zooplankton, squid, mollusks and crustaceans. With no chick to feed, they can explore a wider array of prey.
Coastal vs pelagic waters
Puffins from coastal colonies forage closer to shore and take more benthic prey like crab, mollusks, and sand lance. Their diet relies on whatever prey is accessible in the immediate area.
Pelagic puffins range widely into open ocean and take more offshore schooling fish like herring and capelin. They are not limited by coastal prey availability.
North Atlantic vs North Pacific
Atlantic puffins rely more on sprats, herring, and sand lance. Pacific puffins take more juvenile salmon, anchovy, cod, and smelt.
This reflects key differences in fish abundance and diversity between the two ocean basins.
Diet is influenced by prey availability
Puffin diet and reproductive success is ultimately tied to fluctuations in prey fish stocks. When key prey species decline or disappear from puffin habitats, it threatens their survival. Some impacts:
- Reduced chick growth and survival
- Delayed breeding season
- Complete breeding failure
- Adult mass mortality events
- Colony abandonment
Climate change and human fishing pressure are depleting puffin food supplies in some regions. But puffins are adaptable and can switch prey when needed. Their flexible opportunistic feeding gives them resilience to ecosystem changes.
Unique hunting adaptations
Puffins have evolved remarkable adaptations that allow them to thrive as fish hunters:
- Speedy flapping flight – Allows them to chase down fast schooling fish
- Excellent underwater vision – Enables them to target fish efficiently
- Laterally compressed beak – Allows them to grip several fish simultaneously
- Rough spiny tongue – Helps them hold slippery fish in their beak
- Salt gland – Removes excess salt from sea water they drink and swallow
These traits make puffins formidable fishers allowing them to capitalize on rich marine food webs. Their adaptations ensure they get enough nutrition to breed successfully and raise chicks.
Foraging strategies
Puffins employ various hunting techniques and strategies while foraging at sea to maximize their fish intake:
- Diving – They dive from the surface or air to depths of 60m to pursue fish
- Pursuit diving – Dive rapidly to catch fish fleeing from their approach
- Sit-and-wait hunting – Bob on the surface waiting to ambush fish below
- Underwater flapping flight – Flaps wings to propel through water after speedy fish
- Nocturnal feeding – Use excellent low light vision to hunt at night
Puffins also improve their chance of catching fish by hunting in groups. This condenses small fish into bait balls which are easier to exploit.
Their versatile hunting approaches allow puffins to take advantage of any feeding opportunities they encounter at sea. This flexibility likely evolved to deal with unpredictable marine food webs.
Regurgitating fish to feed chicks
Puffins are famous for catching fish in their beaks and returning to nests to regurgitate food and feed chicks. A puffin will carry 3 to 50 small fish at once back to its nest site, depending on the species.
Parent puffins make these fish feeding trips up to 6 times a day. Chicks gain up to 10% of their body weight daily.
Some key facts about puffin fish feeding behavior:
- Both parents regurgitate fish to feed young
- A chick is fed only whole intact fish, not partial or broken pieces
- If parents return with damaged or insufficient fish, the chick starves
- Chicks beg and tap parents’ beaks to stimulate regurgitation
- Daily feeding rate increases rapidly as the chick grows
This intensive fish provisioning lasts around 6 weeks until the chick fledges. It ensures chicks get plenty of nutrition to develop and fledge successfully from the nest.
Diet studies and research
Ornithologists study puffin diet using various methods including:
- Stomach content analysis – Examining stomach contents of dead specimens for prey remains
- Regurgitate analysis – Collecting and identifying undigested prey items regurgitated by handled birds
- Behavioral observation – Watching puffins carry and handle prey with binoculars or telescopes
- Chick growth rates – Faster growth indicates better fish provisioning
- Tracking technology – Shows where puffins go to find food at sea
These methods provide detailed data on prey types, sizes, proportions and caloric values. The data is used to monitor puffin diet diversity, quality and variation.
Stable isotope analysis of feathers can also provide long-term dietary information. Ratios of carbon and nitrogen isotopes reflect a bird’s relative trophic level and use of inshore vs offshore prey over months or years.
Ongoing puffin diet monitoring provides crucial insight into marine food webs and how prey availability drives reproduction and populations. This guides puffin conservation efforts in the face of climate change and overfishing.
Importance of small fish
The prevalence of small fish in puffin diet demonstrates their importance as forage fish. Sand lance, herring, capelin and other small schooling fish are key prey for many marine predators besides puffins, including:
- Whales
- Dolphins
- Seals
- Sea lions
- Large fish
- Other seabirds
These small nutritious fish form vital links between plankton and larger predators in marine food chains. Overfishing of forage fish stocks can have ecosystem-wide impacts.
Monitoring puffin diet provides insight into forage fish abundance. Declines or disappearances of small fish from puffin diet signal a depleted food web requiring fisheries management and conservation.
Conclusion
In summary, puffins are dependent on small fish like sand lance and herring which comprise 60-80% of their diet. They also opportunistically feed on squid, crustaceans and mollusks. Their flexible foraging strategies and adaptations allow them to exploit prey patches across the northern oceans. Careful monitoring of puffin diet provides a window into the health of marine food webs and helps guide ecosystem-based fisheries management.