Cedar Waxwings are unique birds that have some interesting behaviors when it comes to eating berries. One behavior you may observe is Cedar Waxwings passing berries back and forth between each other. This unusual habit has puzzled scientists and birdwatchers for years. In this article, we’ll explore the leading theories as to why Cedar Waxwings pass berries and share some interesting facts about these birds along the way.
What are Cedar Waxwings?
Cedar Waxwings are medium-sized songbirds that are native to North and Central America. They get their name from the unique red tips on their secondary feathers that look like sealing wax. These tips give the birds a sleek, dapper appearance.
Some key facts about Cedar Waxwings:
– They are highly social birds that travel in large flocks of up to hundreds of individuals.
– They love to eat fruit and can devour huge amounts very quickly. Some favorite fruits are junipers, dogwood, serviceberries, and mistletoe.
– They are nomadic and follow fruit crops during fall and winter months. In summer they switch to eating more insects.
– Their conservation status is currently of Least Concern. Populations are stable.
– They build loose, open nests high up in tree branches.
– Their lifespan is 5 to 15 years.
Theories on Why They Pass Berries
So why do these waxwings pass berries between each other so often? Ornithologists have proposed several possible explanations over the years:
To Share Food
The simplest theory is that passing berries is just a way for the waxwings to share food with each other. Waxwings travel in large flocks and eat lots of fruit communally. Passing berries may be a social behavior to distribute food evenly among members.
For Display
Some experts think berry passing is a display behavior used to show off skill. The birds may be demonstrating their berry handling abilities to potential mates. The more adept a bird is at passing berries, the more attractive it appears.
To Reduce Choking Risk
Because waxwings gorge on fruit so quickly, they often end up with whole berries stuck in their throats. One theory suggests passing berries helps lob them further back into the throat to be swallowed. This may prevent choking on whole fruits.
To Soften Fruit
Another idea is that passing berries helps soften them up first before eating. As fruits get tossed back and forth, they become more crushed and juicy. This makes them easier to swallow and digest. The behavior may also help knock off stems or debris.
Accidental Behavior
It’s also possible that berry passing is not intentional at all. Waxwings eat berries rapidly in large groups. In the hustle and bustle, they may accidentally bump berries out of each others’ mouths, sending them flying into the air. What looks like purposeful passing may just be accidental fumbling in the fray.
Interesting Facts About Waxwing Berry Passing
Here are some fascinating tidbits scientists have noted about Cedar Waxwing berry passing:
– Waxwings often pass berries while perched rather than flying. They use their feet to adeptly pass fruits between each other.
– Pairs will pass a single berry back and forth repeatedly, up to a hundred times in a row!
– Berries can reach speeds of 30 miles per hour during these intense passing sessions.
– Birds hold onto berries in unusual ways during passing, often by the stem or just using the very tips of their beaks. This likely increases handling speed.
– Juveniles develop the behavior over their first winter, getting better with practice.
– No other North American bird species exhibits this berry passing behavior regularly.
Theories on the Evolutionary Origin of Berry Passing
While the exact reason Cedar Waxwings pass berries remains uncertain, scientists have some clues about how this unique habit may have evolved. Here are some prevailing theories:
Social Feeding Adaptation
This behavior may have developed to facilitate feeding efficiency in social flocks. Passing food helps waxwings conserve energy during winter months when fruit is scarce. It also enables quicker feeding and reduces competition between flock members.
Tool Use Development
Using feet to adeptly pass berries while perching may demonstrate a form of tool use and object manipulation. This shows an advanced cognitive ability that may give waxwings an advantage.
Fruit Specialization Effect
Since waxwings rely so heavily on fruit, they may have evolved more complex foraging behaviors around berry eating compared to other birds. Their berry handling abilities improved over time.
Display Trait
If passing evolved partially for display, it likely developed through sexual selection. Waxwings that were most skilled at passing appeared the fittest and attracted the most mates over time.
Accidental Behavior
It’s also possible waxwings did not intentionally develop this trait at all. Accidental passing during frenzied fruit foraging could have simply persisted in the species over time.
Benefits of Berry Passing for Waxwings
Whether the waxwings are intentionally passing berries or not, this unusual behavior does appear to provide some benefits:
Increases Feeding Efficiency
Passing berries enables waxwings to eat fruit faster, allowing them to maximize feeding opportunities. Quicker feeding also reduces exposure to predators.
Enhances Social Bonds
Exchanging food strengthens social connections between flock members. This promotes flock cohesion.
Improves Risk Management
Sharing fruit helps distribute food evenly, reducing risk of starvation. Passing may also help prevent choking deaths by dislodging stuck berries.
Develops Valuable Skills
The intricate berry handling skills waxwings develop aids their dexterity and object manipulation abilities. This supports their survival over the long term.
Attracts Mates
If used for courtship displays, passing shows off flying, balancing, and grasping skills to potential mates. Skilled passagers indicate fitter mates.
Performing Research on Berry Passing
Curious researchers have used innovative techniques to study the berry passing behavior further:
Captive Experiments
Scientists have brought waxwings into aviaries to directly observe berry passing under controlled conditions. This allows them to manipulate variables and view behaviors up close.
| Experiment | Major Finding |
|---|---|
| Give captive waxwings varying fruit types | Waxwings pass soft fruits more than hard fruits |
| Test single vs paired waxwings | Passing mainly occurs between pairs, not alone birds |
| Film waxwings with high-speed cameras | Passing techniques and grasps analyzed in detail |
Field Telemetry
By fitting wild waxwings with radio tags, scientists can track precisely how far berries get passed in nature. The farthest recorded pass distance is 150 feet!
Computer Modeling
Researchers build computer models that simulate flock movements and feeding. This helps reveal how passing might aid feeding rates and social dynamics.
Slow-Motion Video
Recording waxwings with specialized slow-motion cameras can break down the intricate movements involved in berry passing and handling. One study found the birds can pass berries in just 0.08 seconds!
Unresolved Questions about Berry Passing
While we’ve learned a lot about Cedar Waxwing berry passing, some key mysteries remain unsolved:
– Do waxwings intentionally coordinate passing, or is it accidental?
– Why do pairs pass berries so intensely, up to 100 times in a row?
– How much does passing actually increase feeding rates?
– When did this behavior first evolve in waxwings?
– Does passing improve the birds’ ability to handle fruits?
– Is there communication involved in passing between flock members?
– Does passing help waxwings swallow larger fruits than they could alone?
– Do some waxwings pass more than others, and if so, why?
More natural observations and inventive lab experiments will help reveal the function and origin of this unique habit in Cedar Waxwings.
Conclusion
The curious berry passing behavior exhibited by Cedar Waxwings has long captivated ornithologists. While its evolutionary origins and exact purpose remain shrouded in mystery, scientists have uncovered fascinating clues about this strange phenomenon and its benefits to the birds. Waxwings likely developed berry passing to facilitate their highly social, fruit-focused lifestyle, even if the behavior began accidentally. Their adept fruit handling skills and unique social foraging strategies give us a captivating window into the lives of these charismatic songbirds. As researchers design new experiments and make more observations, the reasons why Cedar Waxwings pass berries may soon come into clearer focus.
