The great horned owl, known by the scientific name Bubo virginianus, is a large and powerful owl found across North America. Great horned owls are known for their deep, booming hoots that can be heard up to 5 miles away. However, they have a wide repertoire of vocalizations beyond their typical hoots, including begging calls that sound high-pitched and squeaky.
What is a begging call?
A begging call is a vocalization made by nestling or fledgling birds when they are asking their parents for food. Begging calls tend to be loud, high-pitched, and repetitive, designed to get the attention of the adult birds and encourage them to deliver food.
Great horned owl chicks start making begging calls while still in the nest. These calls increase in frequency and intensity as the chicks get bigger and hungrier. The begging calls help guide the parents back to the nest with food. They continue making begging calls for several weeks after fledging until they become independent hunters.
What does a great horned owl begging call sound like?
The begging call of a great horned owlet sounds like a high-pitched, drawn-out squeaking or screeching. It is very different from the low hoots of adult great horned owls.
To human ears, the begging calls sound somewhat like the noise made by a rusty hinge or a squeaky dog toy. The calls tend to come in a repetitive series, almost like the owlet is crying out insistently for food.
Here is an audio clip of typical great horned owl nestling begging calls:
[insert audio clip]
As you can hear, the demanding squeaks are loud, grating, and repetitive. These attention-grabbing calls serve an important purpose, letting the parent owls know that their young are hungry.
Why do great horned owl chicks make begging calls?
Great horned owlets make loud, squeaky begging calls for the following key reasons:
To signal hunger
The primary reason great horned owlets beg is simple – because they are hungry! The begging calls serve to signal to the parents that their chicks need to be fed.
As the chicks grow, their appetite increases rapidly. They rely completely on their parents to deliver enough food to fuel their growth and development. The begging calls communicate their hunger level and ensure the parents don’t forget to bring enough prey.
To reveal location
Great horned owls don’t build an enclosed nest. The chicks hatch out on a large platform of sticks and twigs assembled by the parents. As they grow, the owlets start to move around this platform.
When returning with food, the adult owls listen for the begging calls to pinpoint exactly where on the nest platform their offspring are located. The calls allow the parents to find the owlets and directly deliver the food.
To compete with siblings
Most great horned owl broods contain 2-3 owlets. These siblings often beg and scramble vigorously with each other to get their share of food.
The begging calls serve as competition between the owlets. The loudest, most frequent beggar often gets fed first by the returning parents. This sibling rivalry ensures that each owlet demonstrates a healthy appetite.
To signal need
In addition to hunger, begging calls communicate other needs of the developing owlets. This includes warmth on cold days or shade from the hot sun.
The parents may respond by brooding the owlets to warm them or positioning themselves to provide shade. So the begging calls serve as an adaptive method to signal various requirements beyond just hunger.
How do the parent owls respond to the begging calls?
The adult great horned owls respond in several important ways to the begging calls of their young:
By delivering food
The primary response is to deliver food, obviously. The adults hunt at night and bring back prey like rabbits, rats, and birds to the nest. When they hear the begging calls, they know it’s time to feed the owlets.
The parents may tear pieces of flesh off the prey item and feed them directly to the begging owlet. Or they may drop the prey onto the nest, allowing the aggressive owlets to rip their own pieces off.
By finding the chick
As mentioned earlier, the begging calls allow the parents to pinpoint the location of the owlets on the messy nest platform. Even in complete darkness, the adults can follow the calls to find the open mouths of the waiting owlets.
By removing waste
In addition to providing food, the parents also keep the nest clean. The begging calls remind the adults to remove waste like discarded food scraps and feces that accumulate on the platform.
This helps keep the owlets’ living space sanitary as they grow. The adults will carry away or eat the waste to tidy up the nest.
By feeding the most hungry
When multiple owlets beg simultaneously, the parent owls tend to prioritize feeding the chick that sounds the hungriest. This ensures that each owlet gets adequate nutrition, even if one is stronger or more dominant than its siblings.
The vigour and urgency conveyed in the begging calls helps guide the adults on which chick needs food the most urgently. It helps distribute the available food fairly.
When do great horned owlets stop begging?
Great horned owlets start making begging calls shortly after hatching, while still blind and covered in white downy feathers. The begging intensifies as they grow. It continues for an extended period after they fledge and leave the nest.
The begging calls gradually fade and stop by the time the owlets are around 12-16 weeks old. By this age they have developed their flight capabilities and honed their hunting skills. They are now able to capture their own prey and no longer rely so heavily on their parents for survival.
The weaning process is gradual, however. Even after stopping begging calls, the fledglings may still solicit food from their parents occasionally for several more weeks as they transition to independence. But the demanding, incessant begging calls fade as the owlets mature and gain self-sufficiency.
Unique adaptations of begging calls
Several unique adaptations make the begging calls of great horned owl chicks effective:
High frequency
The high pitch of the begging squeaks allows them to cut through the environment and be heard by parents from a distance. The frequency falls within the sensitive hearing range of adult great horned owls.
Persistence
Begging calls are incredibly persistent, going on and on continuously for extended periods. This demonstrates the urgency of the chick’s needs to the parents.
Loud volume
The calls are loud enough to be heard even above noisy environments like wind, rain, or other wildlife sounds. This ensures the parents receive the signals even in poor conditions.
Harsh quality
The grating, squeaky quality is hard to ignore and commands attention. It stimulates a response from the adult owls.
Rhythm
The repetitive nature and predictable rhythm of the begging calls makes them hard for the parents to habituate to and tune out.
Difference from adult owl hoots
While great horned owl chicks produce begging calls, mature owls communicate with a different vocalization – the deep, resonant hoots:
Begging Calls | Adult Hoots |
---|---|
High-pitched | Low-pitched |
Squeaky | Booming |
Short in duration | Long in duration |
Fast rhythm | Slow, spaced out |
Made by chicks | Made by mature owls |
As you can see, the begging calls of owlets provide a stark contrast to the typical vocalizations of adult great horned owls. The differences in pitch, tone, rhythm, and context allow both owlets and parents to distinguish these unique sounds in meaning and purpose.
Conclusion
In summary, great horned owl chicks make frequent, loud begging calls to signal their hunger and needs to attentive parents. These distinctive squeaks provide an essential form of communication for the developing owlets. The calls enable the owl parents to find their offspring and deliver sufficient food and care.
The begging calls persist from hatching until independence. They play an important role in the survival and growth of young great horned owls. While very different from the hoots of mature owls, these begging squeaks represent a critical component of great horned owl behavior. They facilitate successful parenting and eventual independence.