Miniature owl flower colored horned owl
Somewhere in the southwestern United States, a tiny owl flapped its wings and flew across the night sky in a northwesterly direction. It is a colorful horned owl, the smallest owl in the jungle, named for the flaming color of its feathers (orange). At this time, perhaps by instinct, or by the movement of the southern constellation and the body clock, this little guy with a pair of black eyes is leaving its winter nest and flying back to a breeding ground in the mountains thousands of miles away.
Also known as the "little horned owl", the fatal disadvantage is that their bodies are only the size of a coffee cup (340 ml), which makes them not only bullied by arboreal mammals such as raccoons and pine martens, but even rodents such as tree squirrels and squirrels drive them out of their nests to feed on eggs or young birds in their nests, so it's no wonder they choose to be nocturnal. However, even at night, they often become dinners for large owls such as owls, long-eared owls and eagle owls that linger in the woods.
Since the 1990s, American scientists have been tracking the colorful horned owl, and their arduous field research has finally led to an understanding of the breeding habits, living environment and difficulties of this small, mysterious miniature owl.
Fatal food shortages
In the life of the colorful horned owl, dangers follow everywhere. Escaping a multitude of predators is dangerous, but the greatest danger they face is not those predators, but their own feeding habits. The chamomile owl feeds on insects, which puts them at risk of severe food shortages. Despite the large number of insects, at night, the number of insects depends on whether the weather is warm and dry, and cold and wet weather tends to reduce the activity of insects. The owls often inhabit high altitudes, and this environment concentrates many unfavorable factors. To make matters worse, although the colorful horned owl is covered with insulated feathers, they can also get cold when exposed to humid night environments for a long time, and maintaining body temperature will consume more of their energy.
The weather in the mountains is volatile, and even a storm that lasts two or three days can put the Cape Owl in a desperate situation. Birds are warm-blooded animals with high body temperatures (an average of 40 °C), and in order to maintain their metabolism, most birds need an adequate food supply, while seasonal long-distance migration, moulting, and reproduction (including competition for territory, spawning and feeding young birds) make birds more nutritionally demanding. But in the mountains, the spring weather is really unreliable. As a result, the "energy crisis" is often the biggest threat to the owls.
Dangerous migration journeys
In the spring, the Chamomile Owl has an unusual migration. If Napoleon's invincible army was "marching by stomach", then the same is true of the migration of the colorful horned owl. Of course, they are not chasing French cuisine, but nocturnal insects, mainly including lepidoptera (moths), coleoptera (beetles) and orthoptera (crickets). For this reason, people also call this small predator "the ghost killer of the order".
In early spring, the western highlands of the United States are covered in residual snow, the weather is still cold, and the insects are still dormant. And at warm, low altitudes, various insects have awakened from winter sleep. Thus began the migration of the owls, which moved north along the lowlands.
The colorful horned owl, which American scientists are following, will fly over the mountains of the western United States and finally reach its destination, Mount Sablat in Idaho, where they nest and breed. On this return journey, they face many dangers. Compared to daytime birds, they have to eat during the nighttime temperature drop, which makes it more difficult for them to eat. The weather in the mountains of the western United States is unpredictable, and during the journey of the cape owl in desperate need of replenishment, if they encounter cold air currents that cause food shortages, they will have to starve. Food shortages can lead to a weight loss of up to 25% for the chamois. If they can't eat for several nights, they starve to death. As a result, some of the cape owl will die on the journey. In addition, if they fly to Mount Sabrit before mid-May, or if they arrive there before the insects appear, they will also be in danger of food shortages.
Arduous courtship and child-rearing
The spring migration is like a life-and-death test for the owls, but even after passing this level, the owls eventually arrive at their destination exhausted, which does not mean that they can breathe a sigh of relief, because the energy requirements of the breeding season are also quite huge, especially for males. Driven by hormones, males weave through the woods and chirp (their low, two-syllable calls are very loud), both to attract any females who might mate with them, and to warn other males not to approach. For females who respond to its song and approach it, it will be offered food as a reward. If you're lucky, its efforts will soon bring it a mate. At this time, it will lead its "fiancée" from tree to tree, until the latter is satisfied, and finally chooses the nesting site. Next, when the "husband" begins the arduous and continuous "marriage and eating behavior". The so-called "marriage feeding behavior", that is, from the beginning of the pairing, until the end of the incubation period, the male is responsible for providing food to his mate. In addition, it patrols its territory and drives other male birds that dare to break in.
For the female, life is not easy. Once paired, they are immediately confronted with the need for energy for reproduction. Still, the females have many benefits to being pursued by males – although they will soon be laying eggs, at least for the time being, they can enjoy a comfortable and comfortable life. They become lazy, do not exercise, and enjoy a lot of food that their suitors pay tribute to. Once they have decided to mate with a male, they spend the night in or by the tree hole of their choice, making a chick-like sound of waiting to be fed. Within weeks, they will regain their strength and be ready to lay their eggs.
As soon as the first egg is laid, the female begins to hatch. After that, the female lays 1 egg every 1 to 2 days and 2 to 4 eggs per clutch. The number of eggs laid reflects the physical condition of the female. Of course, this is also determined by the amount of feeding of the male. If bad weather leads to an inadequate supply of insects, the female's ability to lay eggs is reduced, and in extreme cases it may not lay eggs at all.
The incubation process lasts from 24 to 25 days. If you're lucky, the weather is right to ensure that the male catches enough food for his mate. But if unfortunately, in the event of persistently unfavorable weather, the female will have to leave the hatching eggs to go out and forage on her own to ensure that she can survive. For the eggs and nests, any one of the females leaving for a long time is quite dangerous.
Some scientists have calculated that a female bird with a colorful horned owl in the incubation process eats about 22 insects a day, and during the entire incubation and subsequent brooding process, a pair of colorful horned owl preys on a total of 2314 insects in 49 days. There are also scientists who observe the nests of birds during the breeding period, and the results show that a pair of parents of colorful horned owl return to the nest an average of 65 to 133 times a night, and almost every return to the nest is accompanied by feeding. It can be seen that throughout the breeding season, the demand for insects by the colorful horned owl is staggering, and the "ghost killer" is worthy of the name.
Be loyal to your spouse and your field
Studies have shown that the relationship between the length of birds' wings and the length of migration routes is positively correlated: the longer the wings, the longer the migration routes. The relatively long wings and records of wandering and wandering of the cape owl support their classification into taxa known as "neotropical migratory birds," i.e., terrestrial migratory birds that nest in North America and spend the non-breeding season in the southern United States.
The researchers' field follow-up study found that paired cape owls fly back to the Idaho breeding grounds together in the summer. Despite the long and dangerous journey back, the Cape Owl can still return precisely to a specific nesting site and be loyal to the same mate.
Much of the mountains of the northwestern United States are covered by patchy woodlands, and migratory owls prefer to choose lush woods and shrublands as nesting grounds. This behavioral preference appears to have been shaped by the success or failure of previous generations of reproduction.
Like many other species of small owls, the cape owl builds its nest in an empty tree hole. Therefore, they must rely on the expertise of "beginner nesters" (such as some species of woodpeckers). Sometimes they have to compete with other small owls and local woodpecker populations for nest holes. For example, a couple of flower-horned owl successfully exploited a tree hole in the summer of the first year, but in the second year, they may not compete with other nesting birds for the tree hole.
Unknown population fate
In Idaho, to investigate the nesting reproduction rate of the chamored owl, researchers always marked at night at each spot where the fowl could be heard chirping, and then came during the day to look for nest holes occupied by the capped owl. Experience has taught them that the male can usually be heard in mid-to-late May, and the female is a little later. Therefore, it is probably not until June that the male and female birds occupy the nest hole. However, in the fifth summer, an accident occurred.
Everything happened without warning. Earlier, the male birds were still chirping in the territory as before. After entering June, although the researchers could hear the chirping of the flower-horned owl, they could not find any occupied nest holes. This is still the case by July, when in normal years the owls are already busy feeding their chicks in their nests. The researchers sensed something was wrong: the owls had all returned, but none of them had succeeded in nesting, so where had they all gone? The researchers also found drowning owls in the drinking troughs of livestock, suggesting that the lack of food had forced the owls to venture into the tanks to collect insects.
The researchers tried to find out why, but they couldn't find anything unusual — no fires, no droughts or floods, no changes in herding activities, and no logging. There must be another cause for widespread nesting failures, so what could it be? The reason for the failure of nesting and breeding may be hidden in the shadows of the breeze above the canyon and the clouds on the hillside.
The researchers surveyed the study area's weather records from April to June of that year and calculated the average temperature and precipitation early in the breeding season. By comparing the meteorological data of the first four breeding years with the fifth breeding year, especially the meteorological data of important stages in successful breeding years, such as the physiological recovery period after migration, the marriage period, etc., the researchers finally saw the interaction between the weather (and the consequent change of insect supply) and the success rate of breeding of the flower-horned owl - adverse weather at the critical moment of the breeding period can completely crush the entire breeding population.
Another year has passed, and the sixth breeding season has arrived. As in the fifth year, the area once again experienced cold and wet weather patterns, and the cape owls once again experienced nesting failures across the population. The territory-occupying male chamois horned owls chirped in late May and throughout June, but as in the previous year, the researchers were unable to find even one pair of successful nesting and breeding mates.
Happily, May and June of the seventh breeding season were warmer and drier than the previous two years, and researchers finally found some colorful horned owl that had successfully nested and bred. They also successfully conducted circumnavigations of some families of the cape owl, so that they could use radio tracking to understand the family behavior and whereabouts of the chicks after learning to fly.
Radio tracking showed that the male was responsible for feeding and caring for the first two young birds, who were always around them and only moved on one side of the valley around the nest; the female, after the third (and last) young bird learned to fly, began to take care of the duty, leading the "child" through the fir forest and the understory bush, and using only the other side of the valley. The behavior of both "parents" in caring for different offspring individuals in different areas of the territory is known as the "brood division of labor", and they do so to better avoid predators and improve the effectiveness of brooding.
The reproduction of the Idaho Owls in different years is sobering: the future global climate may warm and dry, may become wet and cold, but in any case, it is not good news for the flowered owl.