Increased or decreased temperature in chickens may indicate internal inflammatory processes. This indicator also affects the productivity and egg production of chickens. Therefore, it is necessary to follow the standards for keeping poultry and know the chicken’s body temperature in normal condition.
Chicken eggs are genetically programmed to develop normally when incubated by a female hen. The brood hen's body heat is of decisive importance here.
Contrary to the opinion of experts, it does not increase, but decreases. In the first week it is 38-39°C, in the last week it rises to 40°C.
Normal body temperature of common species of animals and birds
In case of illness
Chickens are susceptible to many diseases.
The most common are infectious:
- Bronchitis and paralysis;
- Bird flu;
- Colinfection;
- Atypical plague;
- Pasteurellosis.
The first sign of these and other diseases is the occurrence of fever, especially if it is accompanied by the following symptoms:
- Lethargy, refusal to eat;
- Discharge of mucus from the eyes and beak;
- Diarrhea.
Monitoring the temperature of the bird will help diagnose diseases in a timely manner. The temperature of the hen is measured with a thermometer greased with Vaseline, which is carefully inserted into the cloaca. This is the hole through which birds poop.
Hypothermia and hypothermia in chickens
The peculiarity of the body of these birds is such that an increase in temperature of 0.5°C is abnormal and requires the attention of the owner. But this does not always indicate illness.
Other common reasons why a chicken's body temperature deviates from normal are:
- Stress. Chickens quickly become accustomed to routine, and any major changes to their daily routine and environment can cause significant stress. Even a change in diet or transfer to another room can make these birds nervous;
- Heat. If the temperature in the chicken coop or aviary is more than 30°C, the chickens become hot. Heat exchange processes with the environment do not lead to proper cooling of the body due to the lack of sweat glands in these birds.
Important. Hypothermia is also dangerous, especially for chickens and young animals.
Heat stress occurs, which can lead to death from heat stroke.
Overheating is indicated by the behavior of chickens:
- They open their beak;
- They breathe frequently;
- They lie on the ground with half-opened wings.
The temperature threshold is 33°C.
These reasons can be easily eliminated with proper care and compliance with standard requirements for a chicken coop. But if the temperature does not return to normal for more than a day or is elevated by more than a degree, this is a reason to visit the veterinarian.
What does temperature depend on?
For all living beings, normal body temperature depends on internal processes and is optimal for the metabolism inherent in a given species. The more intense it is, the more thermal energy is released during the breakdown of substances in the process of cellular nutrition.
The second important factor is the ambient temperature with which the body of a living creature constantly exchanges heat. In hot weather the body will be warmer, in a cold room it will be colder.
Birds belong to warm-blooded animals with a constant body temperature. A frog can also have warm blood if it is kept in a well-heated room. Flies and mosquitoes, which work their wings vigorously and extremely quickly during flight, may also have a high temperature. But they do not have a constant temperature. Only birds and mammals belong to animals with a constant body temperature. They have perfect thermoregulation, that is, they can maintain a constant temperature in their body, independent of the temperature of the environment.
The body temperature of birds is very high. Significantly higher than in humans. For example, in a song thrush it reaches 45.5 degrees Celsius, and on average for all birds (if we can talk about an average) it is approximately 42 degrees. True, in some species of birds the body temperature is significantly lower than indicated, especially in waterfowl. In particular, in geese and grebes it is 39.9 degrees, while in the Adélie penguin it is only 37.4 degrees.
The high body temperature of birds is associated with some of their physiological characteristics. Birds have a very high metabolic rate. Indeed, hot blood with great speed washes the entire small body of the bird, distributes nutrients, and carries away decay products. This is related to the bird's heart rate. Even the feverish pulse of a person cannot be compared with the “pulse” of a bird. Here are some numbers: the kite has 250 heartbeats per minute, the sparrow has 460, and the tiny hummingbird has an internal motor that works at an incomprehensible speed - more than 1000 beats per minute (just think!). It is natural to expect after this that birds have large hearts. And indeed, in birds, the heart weighs more than one hundredth of the weight of the entire bird. The hummingbird's heart is especially large - almost three hundredths of its body weight, more precisely - 2.75%.
To maintain such high vital energy, you need a lot of food. It has been established that in small birds, which are in more unfavorable heat transfer conditions, almost two-thirds of the food they eat goes to maintaining body temperature. And therefore birds, especially small ones, eat a lot, they are voracious creatures. However, we will talk about the “norms” of bird nutrition in a special section devoted to nutrition. However, one should not exaggerate the homothermism of birds. Some temperature fluctuations are also observed in them, which depends on their activity. Namely: maximum body temperature is observed when the bird shows maximum activity and moves vigorously all the time. The minimum activity and, accordingly, a decrease in temperature occurs during rest, at night. It has been established that in some bird species the difference between their day and night temperatures is 5-6°.
A helpless, naked and blind chick in the nest does not yet have thermoregulation (i.e., the physiological ability to maintain the same body temperature). Its constant temperature is established a few days after hatching, which is why parent birds are forced to keep their chicks warm in the nest all the time. For this reason, in some species the female is constantly present at the nest, while the male (for example, a hawk) has to continuously look for food for both the brood and the female.
Only birds are able to tolerate significant fluctuations in environmental temperature without significant changes in their level of vital activity. When cold weather sets in, the frog becomes lethargic and falls into a stupor. Birds in the cold only need to get more food to compensate for the increased heat loss, so temperature conditions have little direct impact on their lives. The disappearance of insects in winter, the freezing of water bodies, and hence the inability to obtain food in them, cause seasonal migrations, i.e., migrations of birds.
Birds are considered to be more tolerant of temperature constancy than mammals. Among mammals, a number of species are known that enter into the so-called hibernation, for example ground squirrels. What about birds?
Minor fluctuations in temperature depending on the activity of the bird, which have already been mentioned, do not change the idea of birds as animals with a constant temperature. However, in the old days, people thought that the disappearance of migratory birds in the fall was caused not by their flight, but by winter torpor, hibernation. Gophers hide in holes and are not visible in winter. Birds also seem to hide during the winter in shelters inaccessible to humans. It was believed, for example, that swallows dive under water for the entire winter. As for swallows, they are, of course, a legend. But what about old reports of discoveries of (admittedly very rare) torpid birds? It turns out that such messages cannot be dismissed as fictitious. We need to take a closer look at them. In any case, it has now been proven that hummingbirds and swifts can fall into torpor. It is interesting to recall the following fact: smaller and more active birds have the highest body temperatures. The previously mentioned temperature fluctuations, depending on activity, were also noted in more energetic small birds. And hummingbirds are the smallest birds in the world (though not all are so small), and with them these fluctuations sometimes go to extremes, so far that hummingbirds, perhaps, cannot be called warm-blooded creatures at all times. Swifts, although larger than hummingbirds, are also small in size. Hummingbirds can maintain the same level of metabolism in the body only if they constantly eat. At night, their energy expenditure (not compensated by food intake) is so high that their body temperature drops almost to the level of air temperature. In one of the caves in the high-mountainous part of the Andes (in Peru), they once found a numb, lifeless-looking bird - a star hummingbird, which was hanging, frantically clinging to the wall with its paws, while leaning on its tail, as woodpeckers do. This bird's body temperature was 14.5°, only half a degree higher than the air temperature in the cave. It turns out that old reports of “sleeping” birds, which scientists did not pay attention to, had some basis.
When hummingbirds do not receive food for several hours, they sink to the floor of the enclosure, cover themselves with their wings, freeze and appear dead. However, as soon as you pick them up and warm them up, the hummingbirds “awaken” and, if they are immediately offered food, they return to normal life activities. With prolonged hypothermia, hummingbirds die.
In birds that have a constant body temperature, there are no noticeable fluctuations in the duration of incubation depending on changes in temperature. Hummingbirds incubate longer in high altitude areas, particularly in the alpine regions of Mexico. Incubation also occurs in shorter periods of time in tropical countries. In northern Alaska there are very short nights and therefore there is no delay in the development of hummingbird chicks; their parents can feed them almost a full day. In case of low air temperature, hummingbird chicks in the absence of their parents (which usually lasts no more than 8 minutes) become very weak and are no longer able to open their beaks when they appear. All other, “normal” birds in this case do not start feeding, since the feeding reflex manifests itself in them at the sight of the chick’s open beak reaching towards them. And the hummingbirds begin to “force feed” the chick and bring it back to life. They sometimes try to feed even dead chicks, while other birds immediately throw such chicks out of the nest. These are the anomalies observed in the life of such unique birds in many respects as hummingbirds! Swifts are the closest relatives of hummingbirds: they belong to the same order - long-winged. Hummingbirds are found only in America, mainly South America, and swifts (also a separate suborder) inhabit almost the entire globe and nest on all continents. Only most of Australia does not have them. With regard to one of the main properties of the class - body temperature, swifts are very similar to hummingbirds: they are not strictly constantly warm-blooded animals. In case of starvation, their body temperature becomes unstable, sometimes even dropping to plus 20 degrees. Swifts may fall into a stupor. Particularly interesting is the presence of prolonged hunger and torpor in chicks. While the chicks of other insectivorous birds are extremely sensitive to lack of food and die after a one-day, or in extreme cases two-day hunger strike, swift chicks survive a hunger strike for up to nine or even twelve days. Adult swifts cannot withstand such a long hunger strike and die much earlier. In this case we are talking about black swifts.
In many parts of the range * of this swift, a rare summer passes without temporary cold snaps and the associated sharp lack of food - aerial plankton. The suspension of life processes in the chicks that occurs in this case makes it possible for adult birds to leave them without care and move for several days to places where feeding conditions are better. These are the so-called summer, or weather, migrations. However, in this kind of weather migrations, primarily non-breeding birds take part (one-year-old birds in swifts return together with sexually mature birds to their homeland, but do not begin breeding).
* (Habitat is the area of natural distribution of a group of animals (species, genus, etc.).)
The above two features in the ecology of swifts - starvation followed by torpor and weather migrations - should be considered as necessary adaptations to the instability of the food supply. Such adaptations are most clearly manifested in countries subject to frequent summer cyclones, bringing with them cold and rain. include the British Isles, Scandinavian countries and Finland. Observations that made it possible to establish the discussed characteristics of swifts were carried out in England and southern Finland. From this point of view, it would be interesting to monitor the summer movement of swifts in Latvia and Estonia. It is quite possible that in the central regions. In the European part of the USSR, where more stable weather prevails in summer with a predominance of anticyclones, there are no weather migrations. This would confirm the geographical variability of the birds’ lifestyle without the presence of morphological changes.
* (Ecology is one of the biological disciplines that studies the relationship between organisms and the environment.)
Swifts have a reaction to the unfavorable conditions of summer time of a completely different, directly opposite order. Under very unfavorable conditions, which occur during incubation, the swifts throw their eggs out of the nests, regardless of how far the development of the embryo has progressed. Sometimes only part of the masonry is thrown away. As a result of such actions, in a number of places there is no increase in the number of swifts by autumn. In Switzerland, for example, in 1948, based on early summer counts, the appearance of 200 or 230 young swifts was expected.
But on July 27 it was discovered that there were only three young birds, and it was not certain that they would survive to fly from the nest. The duration of the nesting life of swift chicks shows sharp fluctuations depending on weather conditions.
In the most favorable cases, the chicks fly out of the nests on the 38-39th day of life, sometimes even on the 35th or 33rd. In rainy and cold years they stay in the nest for up to 56 days. It was noted that the fewer chicks in the nest, the faster their development occurs. This is apparently due to the fact that they receive more food.
Contrary to the well-known pattern in Ornithology, which is that in more northern individuals the number of eggs in a clutch increases, in swifts, on the contrary, a decrease in the number of eggs is observed. Thus, in Finland and Norway, the average number of eggs in a clutch of a black swift is 2.2, while in Switzerland it is 2.7. Even in this respect they represent an exception to the rule.
The duration of incubation in swifts is also variable; it ranges between 16 and 22 days. In bad weather, the bird spends a lot of time looking for food, and its incubation period is very short. However, in particularly bad weather the bird returns to the nest and sits there; such “brooding,” however, is ineffective, since a hungry bird does not produce the heat necessary for incubation.
One more feature can be noted in the behavior of swifts in nesting areas. Observations in England and southern Finland have established that swifts often fly out in flocks late in the evening into the open sea and spend the entire night on the wing. The duration of the swifts' stay in such a night flight, depending on the time of year and latitude of the area, can range from 4-5 to 7-8 hours. They return to the nest at dawn. Mainly young (i.e., last year’s) non-breeding birds take part in such flights to spend the night at sea. But nesting swifts, apparently, do the same thing, especially those that do not incubate eggs.
Unfortunately, nothing is known in this regard about swifts nesting far from sea shores. It would be good to see whether they spend the night in nests, or whether they also have the peculiar nocturnal “gymnastics” described above. The reason and significance of such night flights of swifts remain unknown. Or maybe these night flights really are a kind of gymnastics aimed at avoiding night stupor. It is known that if a swift spends the night openly, not in a nest, it can fall into torpor.
Very great originality is observed among swifts regarding the timing of autumn (actually summer) departure, which is closely linked to the conditions of the bird’s summer life.
It is widely believed that the arrival of swifts occurs in unison and that the appearance of swifts in the spring means the onset of stable warm weather. Meanwhile, many observations say the opposite. According to Lek's observations made over a number of years in Oxford, it turns out that the arrival of swifts lasts from 18 to 27 days. In this case, the arrival occurs in small parts and often with breaks of one or two or even several days. It is rarely possible to note that the bulk of birds arrive within two or three days. Thus, in 1954, in a supervised colony in Oxford, 62% of all swifts in the colony arrived in three days. It was not possible to detect a more massive arrival. In 1950, with an arrival duration of 23 days (from May 1 to May 23), only a quarter of the birds inhabiting the colony had arrived in the experimental colony by May 5, by May 10 half of all birds were present, and by May 15 - three quarters of the colony. Fluctuations in the average arrival times over 6 years of observations in Oxford are 8 days, from May 8 to May 15. After arrival, several days usually pass before the swifts begin building a nest. The beginning of construction coincides with the onset of stable warm weather.
The summer stay of swifts in nesting areas consists of a short period of time that passes after arrival until the onset of good weather - the time of nest construction (8 days), which varies greatly in the duration of the incubation period (16-22 days) and the nesting life of the chicks, which is equally variable in time. (33-39 days). Let’s add up the numbers in brackets, add another 2-3 days that have passed from arrival to the start of nesting, and we’ll get the duration of the swifts’ summer stay at their nesting sites.
Black swift chicks can fly and feed independently immediately after leaving the nest. Therefore, swifts do not have a period of “family” post-nesting life. It happens that young swifts, as soon as they fly out of the nest, immediately leave their nesting territory. At this time, adult birds can be busy collecting food for the chicks, which they will no longer have to feed. There are opposite cases: the parents (or at least one of them) fly away while the chicks are still in the nest. In both cases, therefore, the chicks begin their independent lives without the help of their parents.
Thus, swifts do not have a rather significant period of time, characteristic of many other bird species, between the chicks leaving the nest and the autumn flight, during which the young birds mature and molt.
For black swifts, the date of autumn departure is closely dependent on how long their nesting period was in a given year and at what time it began. And since both depend on summer weather conditions, we can say that the timing of the autumn departure of swifts depends on the summer weather, and especially on the weather in late May - early June, and not on the nature of autumn. The better the weather in summer, the earlier the swifts nest, the shorter their nesting life cycle and the earlier their autumn departure. It is interesting that the further north the swift nests, the later it flies away - in the south earlier than in the north. In Switzerland, for example, swifts fly away earlier than in Southern Finland.
Different groups (individuals) of swifts usually do not fly away at the same time, and this should always be remembered when setting the date of autumn departure. According to observations in England, young swifts fly away immediately after they leave the nests, but older ones may linger for several more days. If the weather in July was bad, parents stay a little longer. Birds whose laying was unsuccessful fly away before birds that successfully hatched chicks. Immature swifts (hatched from the previous year) that have not started nesting usually fly away later than those that nested.
Swifts are monogamous birds; they form pairs for a long period of time, perhaps for life, however, during migrations, as well as in winter, both members of the pair live without any connection with each other. Apparently, in them, like in many other birds, pairs are restored every year anew, as a result of the return of the male and female to their old nest.
The above-described features of the ecology of black swifts and the resulting features during migration are indeed deviations from what is the rule for all birds. However, all this was established from observations in Finland and England. Some materials in the same direction have been collected in other countries of Western Europe. But since the swift is, in the full sense of the word, a “weather bird”, and weather conditions in summer throughout the territory in which swifts live are far from uniform, it is quite possible to expect significant geographical differences in the ecology of this bird.
THERMOREGULATION IN BIRDS
Birds belong to warm-blooded animals with a constant body temperature. A frog can also have warm blood if it is kept in a well-heated room. Flies and mosquitoes, which work their wings vigorously and extremely quickly during flight, may also have a high temperature. But they don’t have it permanently. Only birds and mammals belong to animals with a constant body temperature. They have perfect thermoregulation, i.e. they can maintain a constant temperature in their body, independent of the temperature of the environment.
The body temperature of birds is very high. Significantly higher than in humans. For example, in a song thrush it reaches 45.5 degrees Celsius, and on average for all birds (if we can talk about an average) it is approximately 42 degrees. True, in some species of birds the body temperature is significantly lower than indicated, especially in waterfowl. In particular, in geese and grebes it is 39.9 degrees, while in the Adélie penguin it is only 37.4 degrees.
The high body temperature of birds is associated with some of their physiological characteristics. Birds have a very high metabolic rate. Indeed, hot blood with great speed washes the entire small body of the bird, distributes nutrients, and carries away decay products. This is related to the bird's heart rate. Even the feverish pulse of a person cannot be compared with the “pulse” of a bird. Here are some numbers: the kite has a heart rate of 250 per minute, the sparrow has 460, and the tiny hummingbird has an internal motor that works at an incomprehensible speed - more than 1000 beats per minute (just think!). It is natural to expect after this that birds have large hearts. And indeed, in birds, the heart weighs more than one hundredth of the weight of the entire bird. Hummingbirds have a particularly large heart—almost three-hundredths of their body weight, or more precisely, 2.75%.
To maintain such high vital energy, you need a lot of food. It has been established that in small birds, which are in more unfavorable heat transfer conditions, almost two-thirds of the food they eat goes to maintaining body temperature. And therefore birds, especially small ones, eat a lot, they are voracious creatures. However, we will talk about the “norms” of bird nutrition in a special section devoted to nutrition. However, one should not exaggerate the homothermism of birds. Some temperature fluctuations are also observed in them, which depends on their activity. Namely: maximum body temperature is observed when the bird shows maximum activity and moves vigorously all the time. The minimum activity and, accordingly, a decrease in temperature occurs during rest, at night. It has been established that in some bird species the difference between their day and night temperatures is 5-6°.
A helpless, naked and blind chick in the nest does not yet have thermoregulation (i.e., the physiological ability to maintain the same body temperature). Its constant temperature is established a few days after hatching, which is why parent birds are forced to keep their chicks warm in the nest all the time. For this reason, in some species the female is constantly present at the nest, while the male (for example, a hawk) has to continuously look for food for both the brood and the female.
Only birds are able to tolerate significant fluctuations in environmental temperature without significant changes in their level of vital activity. When cold weather sets in, the frog becomes lethargic and falls into a stupor. Birds in the cold only need to get more food to compensate for the increased heat loss, so temperature conditions have little direct impact on their lives. The disappearance of insects in winter, the freezing of water bodies, and hence the inability to obtain food in them, cause seasonal migrations, i.e., migrations of birds.
Birds are considered to be more tolerant of temperature constancy than mammals.
Minor fluctuations in temperature depending on the activity of the bird, which have already been mentioned, do not change the idea of birds as animals with a constant temperature. However, in the old days, people thought that the disappearance of migratory birds in the fall was caused not by their flight, but by winter torpor, hibernation. Gophers hide in holes and are not visible in winter. Birds also seem to hide during the winter in shelters inaccessible to humans. It was believed, for example, that swallows dive under water for the entire winter. As for swallows, they are, of course, a legend. But what about old reports of discoveries of (admittedly very rare) torpid birds? It turns out that such messages cannot be dismissed as fictitious. We need to take a closer look at them. In any case, it has now been proven that hummingbirds and swifts can fall into torpor. It is interesting to recall the following fact: smaller and more active birds have the highest body temperatures. The previously mentioned temperature fluctuations, depending on activity, were also noted in more energetic small birds. And hummingbirds are the smallest birds in the world (though not all are so small), and with them these fluctuations sometimes go to extremes, so far that hummingbirds, perhaps, cannot be called permanently warm-blooded creatures. Swifts, although larger than hummingbirds, are also small in size. Hummingbirds can maintain the same level of metabolism in the body only if they constantly eat. At night, their energy expenditure (not compensated by food intake) is so high that their body temperature drops almost to the level of air temperature. In one of the caves in the high-mountainous part of the Andes (in Peru), they once found a numb, lifeless-looking bird - a star hummingbird, which was hanging, frantically clinging to the wall with its paws, while leaning on its tail, as woodpeckers do. This bird's body temperature was 14.5°, only half a degree higher than the air temperature in the cave. It turns out that old reports of “sleeping” birds, which scientists did not pay attention to, had some basis.
When hummingbirds do not receive food for several hours, they sink to the floor of the enclosure, cover themselves with their wings, freeze and appear dead. However, as soon as you pick them up and warm them up, the hummingbirds “awaken” and, if they are immediately offered food, they return to normal life activities. With prolonged hypothermia, hummingbirds die.
In birds that have a constant body temperature, there are no noticeable fluctuations in the duration of incubation depending on changes in temperature. Hummingbirds incubate longer in high altitude areas, particularly in the alpine regions of Mexico. Incubation also occurs in shorter periods of time in tropical countries. In northern Alaska there are very short nights and therefore there is no delay in the development of hummingbird chicks; their parents can feed them almost a full day. In case of low air temperature, hummingbird chicks in the absence of their parents (which usually lasts no more than 8 minutes) become very weak and are no longer able to open their beaks when they appear. All other, “normal” birds in this case do not start feeding, since the feeding reflex manifests itself in them at the sight of the chick’s open beak reaching towards them. And the hummingbirds begin to “force feed” the chick and bring it back to life. They sometimes try to feed even dead chicks, while other birds immediately throw such chicks out of the nest. These are the anomalies observed in the life of such unique birds in many respects as hummingbirds!
Swifts are the closest relatives of hummingbirds: they belong to the same order - long-winged. Hummingbirds are found only in America, mainly South America, and swifts (also a separate suborder) inhabit almost the entire globe and nest on all continents. Only most of Australia does not have them.
With regard to one of the main properties of the class - body temperature, swifts are very similar to hummingbirds: they are not strictly constantly warm-blooded animals. In case of starvation, their body temperature becomes unstable, sometimes even dropping to plus 20 degrees. Swifts may fall into a stupor. Particularly interesting is the presence of prolonged hunger and torpor in chicks. While the chicks of other insectivorous birds are extremely sensitive to lack of food and die after a one-day, or in extreme cases two-day hunger strike, swift chicks survive a hunger strike for up to nine or even twelve days. Adult swifts cannot withstand such a long hunger strike and die much earlier. In this case we are talking about black swifts.
In many parts of the range of this swift, a rare summer passes without temporary cold spells and the associated sharp lack of food - aerial plankton. The suspension of life processes in the chicks that occurs in this case makes it possible for adult birds to leave them without care and move for several days to places where feeding conditions are better. These are the so-called summer, or weather, migrations. However, in this kind of weather migrations, primarily non-breeding birds take part (one-year-old birds in swifts return together with sexually mature birds to their homeland, but do not begin breeding).
The above two features in the ecology of swifts - starvation with subsequent torpor and weather migration - should be considered as necessary adaptations to the instability of the food supply. Such adaptations are most clearly manifested in countries subject to frequent summer cyclones, bringing with them cold and rain. These include the British Isles, Scandinavian countries and Finland. Observations that made it possible to establish the discussed characteristics of swifts were carried out in England and southern Finland. From this point of view, it would be interesting to follow the summer movement of swifts in Latvia and Estonia. It is quite possible that in the central regions of the European part of Russia, where more stable weather prevails in summer with a predominance of anticyclones, there are no weather migrations. This would confirm the geographical variability of the birds' lifestyle without the presence of morphological changes.
Swifts have a reaction to the unfavorable conditions of summer time of a completely different, directly opposite order. Under very unfavorable conditions, which occur during incubation, the swifts throw their eggs out of the nests, regardless of how far the development of the embryo has progressed. Sometimes only part of the masonry is thrown away. As a result of such actions, in a number of places there is no increase in the number of swifts by autumn. In Switzerland, for example, in 1948, based on early summer counts, the appearance of 200 or 230 young swifts was expected.
But on July 27 it was discovered that there were only three young birds, and it was not certain that they would survive to fly from the nest. The duration of the nesting life of swift chicks shows sharp fluctuations depending on weather conditions.
In the most favorable cases, the chicks fly out of the nests on the 38-39th day of life, sometimes even on the 35th or 33rd. In rainy and cold years they stay in the nest for up to 56 days. It was noted that the fewer chicks in the nest, the faster their development occurs. This is apparently due to the fact that they receive more food.
Contrary to the well-known pattern in ornithology, which is that in more northern individuals the number of eggs in a clutch increases, in swifts, on the contrary, a decrease in the number of eggs is observed. Thus, in Finland and Norway, the average number of eggs in a clutch of a black swift is 2.2, while in Switzerland it is 2.7. Even in this respect they represent an exception to the rule.
The duration of incubation in swifts is also variable; it ranges between 16 and 22 days. In bad weather, the bird spends a lot of time looking for food, and its incubation period is very short. However, in particularly bad weather the bird returns to the nest and sits there; such “brooding,” however, is ineffective, since a hungry bird does not produce the heat necessary for incubation.
One more feature can be noted in the behavior of swifts in nesting areas. Observations in England and southern Finland have established that swifts often fly out in flocks late in the evening into the open sea and spend the entire night on the wing. The duration of the swifts' stay in such a night flight, depending on the time of year and latitude of the area, can range from 4-5 to 7-8 hours. They return to the nest at dawn. Mainly young (i.e., last year’s) non-breeding birds take part in such flights to spend the night at sea. But nesting swifts, apparently, do the same thing, especially those that do not incubate eggs.
Unfortunately, nothing is known in this regard about swifts nesting far from sea shores. It would be good to see whether they spend the night in nests, or whether they also have the peculiar night “gymnastics” described above. The reason and significance of such night flights of swifts remain unknown. Or maybe these night flights really are a kind of gymnastics aimed at avoiding night stupor. It is known that if a swift spends the night openly, not in a nest, it can fall into torpor.
Very great originality is observed among swifts regarding the timing of autumn (actually summer) departure, which is closely linked to the conditions of the bird’s summer life.
It is widely believed that the arrival of swifts occurs in unison and that the appearance of swifts in the spring means the onset of stable warm weather. Meanwhile, many observations say the opposite. According to Lek's observations made over a number of years in Oxford, it turns out that the arrival of swifts lasts from 18 to 27 days. In this case, the arrival occurs in small parts and often with breaks of one or two or even several days. It is rarely possible to note that the bulk of birds arrive within two or three days. Thus, in 1954, in a supervised colony in Oxford, 62% of all swifts in the colony arrived in three days. It was not possible to detect a more massive arrival. In 1950, with an arrival duration of 23 days (from May 1 to May 23), only a quarter of the birds inhabiting the colony had arrived in the experimental colony by May 5, by May 10 half of all birds were present, and by May 15 - three quarters of the colony. Fluctuations in the average arrival times over 6 years of observations in Oxford are 8 days, from May 8 to May 15. After arrival, several days usually pass before the swifts begin building a nest. The beginning of construction coincides with the onset of stable warm weather.
The summer stay of swifts in nesting areas consists of a short period of time that passes after arrival until the onset of good weather - the time of nest construction (8 days), which varies greatly in the duration of the incubation period (16-22 days) and the nesting life is equally variable in time. chicks (33-39 days). Let’s add up the numbers in brackets, add another 2-3 days that have passed from arrival to the start of nesting, and we’ll get the duration of the swifts’ summer stay at their nesting sites.
Black swift chicks can fly and feed independently immediately after leaving the nest. Therefore, swifts do not have a “family” period after nesting life. It happens that young swifts, as soon as they fly out of the nest, immediately leave their nesting territory. At this time, adult birds may be busy collecting food for the chicks, which they will no longer have to feed. There are opposite cases: the parents (or at least one of them) fly away while the chicks are still in the nest. In both cases, therefore, the chicks begin their independent lives without the help of their parents.
Thus, swifts do not have a rather significant period of time, characteristic of many other bird species, between the chicks leaving the nest and the autumn flight, during which the young birds mature and molt.
For black swifts, the date of autumn departure is closely dependent on how long their nesting period was in a given year and at what time it began. And since both depend on summer weather conditions, we can say that the timing of the autumn departure of swifts depends on the summer weather, and especially on the weather in late May - early June, and not on the nature of autumn. The better the weather in summer, the earlier the swifts nest, the shorter their nesting life cycle and the earlier their autumn departure. It is interesting that the further north the swift nests, the later it flies away - in the south earlier than in the north. In Switzerland, for example, swifts fly away earlier than in Southern Finland.
Different groups (individuals) of swifts usually do not fly away at the same time, and this should always be remembered when setting the date of autumn departure. According to observations in England, young swifts fly away immediately after they leave the nests, but older ones may linger for several more days. If the weather in July was bad, parents stay a little longer. Birds whose laying was unsuccessful fly away before birds that successfully hatched chicks. Immature swifts (hatched from the previous year) that have not started nesting usually fly away later than those that nested.
Swifts are monogamous birds; they form pairs for a long period of time, perhaps for life, however, during migrations, as well as in winter, both members of the pair live without any connection with each other. Apparently, with them, like many others
birds, pairs are restored every year anew, as a result of the return of the male and female to their old nest.
The above-described features of the ecology of black swifts and the resulting features during migration are indeed deviations from what is the rule for all birds. However, all this was established from observations in Finland and England. Some materials in the same direction have been collected in other countries of Western Europe. But since the swift is, in the full sense of the word, a “weather bird,” and weather conditions in summer throughout the territory in which swifts live are far from uniform, one can well expect significant geographical differences in the ecology of this bird.
Birds have a higher body temperature than mammals. What advantages does this give to birds and what are the disadvantages associated with it?
High body temperature provides two main benefits to birds. At this temperature, all vital processes occur faster and, in particular, the speed of contraction of muscle fibers is higher. This allows the bird’s muscles to do more work per unit of time, that is, to develop more power. High power density is an adaptation for flight (high power per unit weight is an important characteristic of aircraft engines). Flight involves large losses of energy. To compensate for them, rapid combustion of food and a lot of oxygen are necessary. High body temperature ensures a high level of metabolism and rapid contractions of the heart muscle. The second advantage is related to the process of incubation of eggs. Incubation is an important and dangerous period in the life of birds. High body temperature allows you to shorten its duration.
The main disadvantage of high body temperature is large losses due to heat transfer, which depends on the temperature difference between the body and the environment. This is associated with the need for more frequent and plentiful feeding, and rapid death in the absence of food, especially in cold weather. The birds' strong dependence on the availability of food forces them to undertake seasonal migrations, which often involves the death of many birds. Birds' high body temperatures pose a risk of overheating. When flying, a lot of heat is generated, and the birds' air sacs act as a cooling system. However, at high air temperatures, long flight of birds is impossible.
Caring for chickens is a labor-intensive process that requires sufficient knowledge. Birds, like humans, are susceptible to various diseases, and this can be caused by either hypothermia or excessive heat. The chicken’s body temperature directly depends on how warm or cold it is outside and indoors. The norm should be approximately 41 o C. Both excessive cold and unbearable heat cause illness in birds and lead to various diseases.
Hypothermia in chickens
During significant cold weather, the body is not able to retain heat, and therefore the body temperature of chickens decreases, which can lead to various diseases. There are three types of hypothermia:
- mild hypothermia, in which the bird’s temperature drops to 35 o C;
- average hypothermia - decreases by another 10 o C and is already 25 o C;
- severe degree of cooling, in which the body is cooled to 15 o C.
Chickens aren't the only ones that can suffer from hypothermia. Hypothermia harms all types of poultry, but chicks are most susceptible to it, since their bodies have virtually no thermoregulation. As a result, the birds die, but even if they manage to survive, it is extremely difficult to return to normal; they are sick for a very long time.
In young individuals, hypothermia occurs due to the inability to maintain a stable body temperature within normal limits. Therefore, during the first month of their life, chickens need additional heating, since if they deviate from the proper temperature regime, the death of the brood occurs very soon. Also, do not allow the chickens' down to get wet.
A decrease in the body temperature of chickens occurs not only due to cold weather, but also due to excess humidity in the chicken coop, due to drafts. This also happens due to birds walking during dew, especially if it is heavy. Adult chickens are not as susceptible to hypothermia as young chickens, but the combination of cold and high humidity can certainly lead to hypothermia.
Symptoms and treatment of hypothermia in chickens
First, you need to diagnose hypothermia in the bird: it begins to tremble, the skin and mucous membranes become noticeably cooler, and the chicken itself is constantly looking for a place where it can warm up. Appetite disappears and diarrhea may occur. The bird becomes lethargic and weak, drowsiness overcomes it, and discharge may appear from the nasal passages.
Treatment of chickens with hypothermia may vary depending on the degree of its severity, but all measures should consist of intensive warming of the bird, namely: placing it in a warm and dry room, drinking plenty of warm water.
To prevent hypothermia in chickens, you can lubricate their skin with fat, and it is also important to take care of the warmth and dryness of the area where they are kept.
The effect of high temperatures on the condition of chickens
Heat stress, like hypothermia, leads to extremely negative consequences for the health and life of chickens. Thus, already at an air temperature of 32 o C, the death of poultry begins. A peculiarity of chickens is the absence of sweat glands, which greatly complicates their thermoregulation. They give off excess heat thanks to areas of the body without feathers, which are extremely few. When the air temperature reaches the bird's body temperature, it becomes impossible to give off excess heat through the skin and it can only get rid of heat through the beak. She saves herself by breathing rapidly, which causes her to lose significant weight, and if this procedure does not bring results, the chicken dies.
High temperatures are extremely difficult for chickens to tolerate; they refuse to eat, spread their drooping wings, trying to find coolness near the ground. They experience stunted growth, the quality of the eggs decreases significantly, the size decreases, and the shell becomes very thin.
Helping chickens in high temperatures
First of all, you should organize airflow in the chicken coop, which will significantly reduce the body temperature of individuals. The evaporative cooling method, in which the poultry house is equipped with a special cooling system, is also effective. In this case, air from the street passes through the wet paper and reaches the room 10 o C lower. It is extremely important that birds have enough water, as when the air temperature is high, their consumption increases up to eight times. Feeding is best done in the early morning and late evening hours, when the bird is least susceptible to the effects of heat, and the calorie content of the feed needs to be increased. Electrolyte water can be added to drinking water to replenish the loss of beneficial microelements in the chicken’s body.
The negative effects of both heat and cold on the body of birds can be reduced if the disease is diagnosed in a timely manner. To find out what the chicken's body temperature is, you can measure it. Housing conditions must be comfortable and optimal in order for the condition of the livestock to be stable.
