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Discover the Fascinating Life of Northern Bobwhite: From Diet to Breeding

Black-backed Bittern, scientifically known as Ixobrychus dubius, is a small species of heron found in South and Southeast Asia. Despite being widely distributed, it is a secretive bird that is not commonly seen due to its nocturnal and crepuscular habits.

In this article, we will explore the identification, field markings, and plumages of the black-backed bittern, along with its molts.

Identification

Field Identification

The black-backed bittern is a small, stocky heron that measures around 44-57 cm in length. It has a distinctive black patch on its back that differentiates it from other bittern species.

The upperparts of the bird are dark brown, while the underparts are buff or whitish. The head is small, with a thick neck and a black stripe from the eye to the nape.

The bill is yellow, and the eyes are yellow or greenish-yellow. The legs and feet are greenish-yellow or olive-colored.

Similar Species

The black-backed bittern can be confused with the cinnamon bittern (Ixobrychus cinnamomeus), which is a smaller bird with a chestnut-colored back. However, the cinnamon bittern lacks the black stripe on its head that is present in the black-backed bittern.

Moreover, the cinnamon bittern has a shorter bill and legs than the black-backed bittern.

Plumages

The plumage of the black-backed bittern is not sexually dimorphic, meaning both sexes have the same coloration. However, the juveniles have a different plumage from the adults, which changes as they age.

Juvenile plumage: Juvenile black-backed bitterns have dark brown upperparts with buff or whitish underparts. They also lack the black patch on their backs.

The head is streaked with dark brown and buff, and the bill is brownish-yellow. Adult plumage: In the first year of their lives, black-backed bitterns undergo a pre-basic molt, which results in a new plumage.

In this plumage, the black-backed bittern has a distinctive black patch on its back, dark brown upperparts, and buff or whitish underparts. The bill is yellow, and the eyes are yellow or greenish-yellow.

The legs and feet are greenish-yellow or olive-colored.

Molts

Molting is a natural process in which birds shed their old feathers and replace them with new ones. Black-backed bitterns undergo two types of molts – pre-basic molt and pre-alternate molt.

Pre-basic molt: The pre-basic molt occurs in the first year of their lives and results in a new feather growth. During this process, the old feathers are replaced with new ones which give the juvenile a new adult-like plumage.

Pre-alternate molt: The pre-alternate molt occurs in the breeding season, just before the breeding period and results in a change of the feathers. During this molting period, the feathers of the black-backed bittern change color, giving the bird a new look.

Conclusion

Overall, the black-backed bittern is an interesting bird species that is known for its elusive nature. With a distinctive black patch on its back, dark brown upperparts, yellow bill, and greenish-yellow or olive-colored legs and feet, the black-backed bittern is easily identifiable.

Its plumage changes as it matures and undergoes pre-basic and pre-alternate molts. By studying such birds, we can better understand the intricate nature of our feathered friends and the importance of nature conservation.

Systematics History

The Northern Bobwhite, scientifically known as Colinus virginianus, belongs to the family of New World quails known as Odontophoridae. The earliest classification of this species was by Carolus Linnaeus in 1758, where he named it Tetrao virginianus.

However, the name Colinus was given to this species in 1816 by Constantine S. Rafinesque.

Geographic Variation

The Northern Bobwhite is distributed throughout much of North America, from southern Canada to Mexico. Its range stretches from the eastern seaboard to the Great Plains, and as far west as Arizona.

Throughout this vast range, there is a considerable amount of geographic variation in plumage, size, and vocalizations.

Subspecies

The Northern Bobwhite is divided into over 20 recognized subspecies, each with its unique range and characteristics. They are:

1.

Colinus virginianus mexicanus: Found in Mexico

2. Colinus virginianus cubanensis: Found in Cuba

3.

Colinus virginianus floridanus: Found in Florida

4. Colinus virginianus texanus: Found in South Texas

5.

Colinus virginianus taylori: Found in South-central Texas

6. Colinus virginianus wagneri: Found in Southwestern Arizona

7.

Colinus virginianus ridgwayi: Found in South-central and southeastern states of the USA

8. Colinus virginianus brccides: Found in Baja California and northwestern Mexico

9.

Colinus virginianus albiliventris: Found in Central Mexico

10. Colinus virginianus sennetti: Found in the Mexican state of Guerrero

11.

Colinus virginianus auropectus: Found in the Mexican state of Veracruz

12. Colinus virginianus douglasii: Found in the western United States and western Canada

13.

Colinus virginianus hurdus: Found in southeastern New Mexico, western Texas, and northeastern Chihuahua

14. Colinus virginianus floridianus: Found in southeastern USA

15.

Colinus virginianus virgiananus: Found in eastern USA

16. Colinus virginianus copei: Found in Missouri and southern Illinois

17.

Colinus virginianus maculatus: Found in eastern Texas, western Louisiana, and south-central Oklahoma

18. Colinus virginianus taylori: Found in south-central Texas

19.

Colinus virginianus u.s. woodhousei: Found in southwestern USA and northwestern Mexico

20. Colinus virginianus parkesi: Found in northern Texas and southern Oklahoma

21.

Colinus virginianus mexicanus: Found in Mexico

Related Species

The Northern Bobwhite is related to several other species of quail, including the California Quail (Callipepla californica), Gambel’s Quail (Callipepla gambelii), and Scaled Quail (Callipepla squamata). These species have similar appearances and are usually found in the same areas as the Northern Bobwhite.

Historical Changes to Distribution

The Northern Bobwhite was once widely distributed throughout much of North America. However, over the last few decades, its range has significantly declined due to habitat loss, over-hunting, and increased predation.

This decline has been particularly problematic in the northeast, where populations have plummeted, and the birds are no longer found in many areas where they were once abundant. As an example, in New York State, the Northern Bobwhite once occurred in 50 counties and was a popular game bird, with annual harvests totaling over 1 million birds.

However, in recent years, the species has become increasingly rare, and there are only a few known populations remaining in the state. Similarly, in Alabama, populations have declined by over 80% since the early 1960s, with many areas reporting no sightings for several years.

The decline in populations has been linked to habitat loss due to intensive agriculture practices, fire suppression, and urbanization. Additionally, increased predation from non-native species such as raccoons and opossums and the lack of adequate habitat for nesting and brood-rearing has also impacted populations.

In conclusion, the Northern Bobwhite is a significant species of quail that is widely distributed throughout North America. Its range comprises over 20 recognized subspecies, each with unique characteristics.

Populations have experienced significant declines in recent decades due to habitat loss, predation, and over-hunting. Understanding the historical changes to distribution is vital in the conservation and management of the species, and efforts to restore its habitats are crucial for the survival of the Northern Bobwhite.

Habitat

The Northern Bobwhite is a bird of open grasslands, shrublands, and agricultural lands. It prefers habitats with a mix of dense vegetation for cover and open areas for foraging.

Bobwhites are a ground-dwelling species, and they spend a significant amount of time on the ground, feeding, roosting, and nesting.

Bobwhites prefer to inhabit areas with a diverse mix of vegetation.

The presence of native grasses, forbs, and shrubs is essential for their survival. In winter, they move to areas with abundant cover to protect themselves from the cold.

It is also essential that the habitat provides a clean source of water for drinking and bathing.

Movements and Migration

Northern Bobwhites are not strong flyers, and most of their movements occur on foot. They can travel long distances, however, if necessary.

Bobwhites are non-migratory birds, but they do engage in seasonal movements between different habitats. In general, bobwhites stay within a 2-3 mile radius of their home range.

During the breeding season, male bobwhites establish their territories and begin to call to attract females. Males also engage in aggressive displays, such as puffing up their chests and spreading their tail feathers to intimidate rivals and protect their territories.

Females are attracted to males with the strongest and most consistent calls. After the breeding season, bobwhites form coveys, which are groups of birds that roost and feed together.

Coveys can consist of 6-30 individuals, and they are typically made up of mixed-sex and age groups. The covey’s primary function is to provide protection from predators and to increase the chances of finding food.

During the winter months, coveys may move into areas with better cover to protect themselves from harsh weather conditions. When the breeding season starts again, male bobwhites will leave the covey and set up territories to attract females.

Females then leave the covey to mate and lay eggs. Bobwhites do not form pairs that mate for life.

However, males and females may mate with each other multiple times during a breeding season. Northern Bobwhite populations are declining across its range, and habitat loss is one of the main reasons for the decline.

Development, urbanization, and conversion of grasslands to agricultural fields all contribute to habitat loss. Additionally, changes in land-use practices, such as the use of non-native grasses, and the use of pesticides and herbicides, also contribute to the loss of suitable habitat.

In conclusion, Northern Bobwhites have specific habitat preferences and engage in seasonal movements between different habitats to support their survival. They are non-migratory birds but engage in seasonal movements between habitats.

Habitat loss is the primary reason for the species’ decline, and efforts to restore and protect suitable habitats are essential for the continued survival of these beautiful birds.

Diet and Foraging

Feeding

Northern Bobwhites are primarily granivorous birds, meaning that seeds make up the major part of their diet. They also feed on insects, wild fruits, and some plant material.

Bobwhites are ground-feeding birds and spend a considerable amount of time on the ground, foraging for food. They are opportunistic feeders and will feed on whatever is available in their environment.

Diet

The diet of Northern Bobwhites varies depending on seasonal availability. During the spring and summer, they feed on a variety of insects, including grasshoppers, beetles, and caterpillars.

In the fall, as seeds mature, they become a more significant part of the bird’s diet. Bobwhites also feed on the fruits of native plants, such as blackberries and elderberries.

Seed-eating birds, such as Northern Bobwhites, must be able to digest the tough outer shells that protect the seeds from harm.

Metabolism and Temperature Regulation

Bobwhites have a unique physiology that allows them to regulate their body temperatures in a variety of environmental conditions. Northern Bobwhites are endothermic birds, meaning that they maintain their body temperature by generating metabolic heat through their activity.

Bobwhites use a process called torpor to conserve energy during periods of extreme cold or heat. Torpor is a state of reduced metabolic activity, in which body temperature drops and heart rate slows to a minimum.

Bobwhites also have the ability to pant to help regulate body temperature during periods of extreme heat.

Sounds and Vocal Behavior

Vocalization

Northern Bobwhites are known for their distinctive calls, which are used for communication and identification. Males have louder and more consistent calls than females, and their calls are an essential part of their breeding behavior.

The breeding call of the male is often referred to as the “bobwhite” whistle, which sounds like two clear notes, bob-white. The frequency and duration of the note vary depending on the individual bird.

Bobwhites use different calls for other purposes as well. For example, a low, gurgling call is used by males to attract females during courtship, and a series of soft clucks is used between birds in a covey to communicate.

Bobwhites, like many bird species, also use body language to communicate, such as puffing up their feathers or spreading their wings to display aggression or submission. In conclusion, Northern Bobwhites are primarily granivorous birds that feed on seeds, insects, fruits, and other plant materials.

They have an interesting physiology that allows them to regulate their body temperature in a variety of environmental conditions. Bobwhites are also known for their distinctive calls and vocalizations, which are used for communication and identification.

Understanding the diet, foraging behavior, temperature regulation, and vocal behavior are essential for the conservation and management of this important species.

Behavior

Locomotion

Northern Bobwhites are ground-dwelling birds that move around mostly by walking and running. They use their wings for short bursts of flight but rely primarily on their strong legs to move quickly on the ground.

The birds can move up to eight miles per hour when running, and they can cover a considerable distance quickly when necessary. Bobwhites are agile and can move through dense vegetation with ease.

Self Maintenance

Like most birds, Northern Bobwhites spend a significant amount of time grooming themselves. Grooming is essential for keeping feathers clean, healthy, and well-oiled.

Bobwhites bathe in dust or dry sand to remove excess oil and dirt from their feathers, and they also preen their feathers to remove any parasites or debris. Additionally, bobwhites stretch their wings and legs to keep their muscles limber and to help avoid injuries.

Agonistic Behavior

Northern Bobwhites are territorial birds and are known to engage in aggressive behavior towards other birds of the same species. Males will often puff up their feathers, spread their tails, and engage in mock fights to defend their territories and to attract females.

These displays are typically enough to discourage other males from encroaching on their territory.

Sexual Behavior

During the breeding season, males establish territories and call to attract females. They also engage in aggressive displays to intimidate rivals and to protect their territory.

Females are attracted to males with the strongest and most consistent calls. The male will then court the female with displays of affection, such as offering food or performing dances.

Once the pair has mated, the female will search for a suitable nesting site to lay her eggs.

Breeding

The breeding season for Northern Bobwhites begins in early spring and lasts through to early summer. Males establish territories and call to attract females.

They also engage in aggressive displays to intimidate rivals and to protect their territory. Females are attracted to males with the strongest and most consistent calls.

Once the pair has mated, the female will lay a clutch of 10-12 eggs in a nest on the ground. Both the male and female take turns incubating the eggs for approximately 23 days.

After the eggs hatch, the male and female bobwhites care for the young birds until they can fend for themselves. The young birds are known as chicks, and they are precocial, which means they are born with fully formed downy feathers and are capable of walking and feeding themselves shortly after hatching.

The female will care for the chicks and will lead them to foraging sites for food.

Demography and Populations

Northern Bobwhites are declining across their range, and habitat loss is one of the main contributors to the decline. Many grasslands and shrublands have been converted to farmland or have been destroyed by urbanization, which has reduced suitable habitats for Northern Bobwhites.

Additionally, changes in land-use practices, such as the use of non-native grasses, and the use of pesticides and herbicides, also contribute to the loss of suitable habitat. Populations have also declined due to hunting, as bobwhites are a popular game bird.

In some areas, hunting pressure has been so intense that populations have been unable to recover. Currently, populations of Northern Bobwhites are considered stable in some areas but declining in others, and efforts to restore and protect suitable habitats are essential for the continued survival of these beautiful birds.

In conclusion, Northern Bobwhites have unique behaviors related to locomotion, self-maintenance, agonistic, and sexual behavior. The breeding and demography of the

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