6-6-2019 KHWAI CAMP, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

The water thick-knee or water dikkop (Burhinus vermiculatus) is a species of bird in the thick-knee family Burhinidae. The species is found across sub-Saharan Africa, usually close to water.

The water thick-knee is a terrestrial feeder that forages at night. Although it is typically associated with water it can be found foraging up to 1 km (0.62 mi) from water. It feeds on insects, crustaceans and mollusks.

The water thick-knee has a widespread distribution in sub-Saharan Africa, being found in Angola, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Eswatini, Ivory Coast, Ethiopia, Gabon, Ghana, Kenya, Liberia, Malawi, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Somalia, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe.

Across its range it is found on the edges of lakes, estuaries and rivers, as well as mangroves and also some sheltered beaches. It also needs bushes or nearby woodlands for shelter. It is found from sea-level to 1,800 m (5,900 ft).

The water thick-knee generally breeds in the dry season or early rainy season. It is a monogamous breeder with both parents guarding the nest and brooding the eggs. The nest is a simple scrape in sandy or stony ground, usually close to water. The clutch size is two sandy-yellow eggs. Both sexes incubate the eggs for 22-25 days, and both are responsible for feeding the young. Unique among birds, thick-knee pairs frequently nest adjacent to and sometimes directly on top of Nile crocodile nests. The two species share a form of symbiotic mutualism with the more energetic and vocal thick-knee functioning as loud sentries for the nests as the more powerful crocodile provides protection. Should a nest raider approach, the thick-knee pair will spread their wings in a threat display and harass and peck at the intruders to drive it off. If the pair not be successful, the mother crocodile will be drawn in by their continued calls and arrive.

Appearance: Mottled brown, grey, and white for camouflage, large yellow eyes, short stout bill, and prominent leg joints.

Habitat: Lives near permanent water like rivers, mangroves, and wetlands in sub-Saharan Africa, though it forages up to a kilometer away.

Behavior: Primarily nocturnal and crepuscular (active at dawn/dusk), resting hidden during the day and calling loudly at night.

Diet: Insects, crustaceans, mollusks, frogs, and small reptiles, found by foraging on muddy or sandy areas.

Nesting: Builds a simple scrape on sandy ground, often near water, with perfectly camouflaged eggs.

Unique Symbiosis: Famously nests near Nile crocodiles; the thick-knees act as alarm systems with their calls, and the crocodiles deter predators from the thick-knee's vulnerable eggs.

Name Origin: "Thick-knee" refers to its prominent ankle joints, not its actual knees, possibly due to standing long hours. 

6-6-2019 MOREMI CAMP, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

https://www.inaturalist.org/taxa/4926-Burhinus-vermiculatus

6-6-2019 KHWAI CAMP, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

The water thick-knee is a nocturnal bird found in sub-Saharan Africa that lives near freshwater. It forages for insects, crustaceans, and small vertebrates up to 1 km from water, and its diet can include a wide range of invertebrates and small vertebrates. It nests in a simple scrape on the ground and forms a unique symbiotic relationship with Nile crocodiles, where the birds act as sentries for the crocodiles' nests. 

Habitat and diet

Habitat: Found near rivers, lakes, estuaries, and beaches in sub-Saharan Africa.

Nocturnal behavior: Active at dawn, dusk, and night, though they can be seen during the day.

Foraging: Forages on the ground, sometimes up to a kilometer away from water.

Diet: Primarily feeds on insects, crustaceans (like crabs), and mollusks (like snails), but also eats frogs, tadpoles, and other small vertebrates. 

Breeding and nesting

Nesting: Builds a simple scrape in the ground, often near rocks or other structures for camouflage.

Eggs: Lays 1-3 sandy-yellow eggs, which both parents incubate for 22-25 days.

Parental care: Both parents are responsible for brooding the eggs and feeding the young, which fledge at around two months. 

Symbiotic relationship with Nile crocodiles

Mutualism: Often nests adjacent to or even on top of Nile crocodile nests.

"Sentry" duty: The loud and energetic thick-knees act as sentries, harassing and pecking at potential nest raiders.

Crocodile protection: If the thick-knees cannot drive off the intruder, their calls can alert the mother crocodile, which then protects its nest. 

Physical characteristics

Appearance: A terrestrial wading bird with large yellow eyes, a stout bill, and thick ankles.

Camouflage: Has cryptically colored plumage that blends in with sandy and rocky environments.

Size: Grows to about 38-41 cm in length and weighs around 440g. 

6-6-2019 MOREMI CAMP, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus) COURTESY OF MRS VALERIE FISHER

The Water Thick-knee (Burhinus vermiculatus) is a distinctive African bird known for its large yellow eyes, cryptic plumage, and surprisingly thick leg joints, often found near water bodies in Sub-Saharan Africa, feeding nocturnally on insects and amphibians, and famously forming a mutualistic relationship with crocodiles for nest protection. 

Key Facts:

Appearance: About 38-41cm long, brown/grey mottled, large yellow eyes, short stout bill, and prominent "thick knees" (actually ankles).

Habitat: Prefers freshwater wetlands like riverbanks, lakes, and mangroves, usually within 1km of water.

Behavior: Mostly nocturnal or crepuscular (dawn/dusk), foraging for insects, mollusks, frogs, and tadpoles; they prefer to run than fly when disturbed.

Nesting: A simple scrape in sand or gravel near water, often on sandbars.

Unique Symbiosis: Pairs often nest right next to or on crocodile nests, using their loud calls and threat displays to alert crocodiles to predators (like monitor lizards) in exchange for protection.

Diet: Insects, crustaceans, mollusks, frogs, tadpoles, and seeds.

Family: Part of the stone-curlew/thick-knee family (Burhinidae).

Status: Least Concern (IUCN) due to large range, though nomadic in response to water levels. 

21-5-2019 MANA POOLS, ZIMBABWE - WATER THICK NEE (Barhinus Vermiculatus)

The water thick-knee or water dikkop (Burhinus vermiculatus) is a species of bird in the thick-knee family Burhinidae. The species is found across sub-Saharan Africa, usually close to water.

The water thick-knee has a widespread distribution in sub-Saharan Africa, being found in Angola, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Eswatini, Ivory Coast, Ethiopia, Gabon, Ghana, Kenya, Liberia, Malawi, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Somalia, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe.

Across its range it is found on the edges of lakes, estuaries and rivers, as well as mangroves and also some sheltered beaches. It also needs bushes or nearby woodlands for shelter. It is found from sea-level to 1,800 m (5,900 ft).

6-6-2019 KHWAI CAMP, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

15-4-2018 CHOBE RIVER, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

The Water Thick-knee, also known as the Water Dikkop (Burhinus vermiculatus), presents a striking figure with its 38 to 41 cm (15–16 in) stature and a weight range of 293–320 g (10.3–11.3 oz). This bird is characterized by a robust bill, black with a hint of yellow at the base, broad and blunt wings, and a rather short tail.

When identifying the Water Thick-knee, look for its heavy bill with a yellow base, which is quite distinctive. The wings are broad and blunt, which can be observed when the bird stretches them. The tail is short, which is noticeable when the bird is in flight or when it fans its tail feathers.

The Water Thick-knee is typically found along the edges of lakes, estuaries, and rivers. It also frequents mangroves and some sheltered beaches, often requiring nearby bushes or woodlands for shelter. Its habitat range extends from sea level up to 1,800 m (5,900 ft).

This species enjoys a widespread distribution across sub-Saharan Africa, with sightings reported in countries such as Angola, Botswana, Burkina Faso, and many others, all the way to South Africa.

The Water Thick-knee is a nocturnal terrestrial feeder, often venturing up to 1 km (0.62 mi) away from water to forage. It is known for its unique nesting behavior, often laying its eggs adjacent to or directly on top of Nile crocodile nests, engaging in a symbiotic mutualism with the crocodiles.

5-4-2018 CHOBE RIVER, NAMIBIA - WATER THICK NEE (Barhinus Vermiculatus)

The Water Thick-knee, also known as the Water Dikkop (Burhinus vermiculatus), presents a striking figure with its 38 to 41 cm (15–16 in) stature and a weight range of 293–320 g (10.3–11.3 oz). This bird is characterized by a robust bill, black with a hint of yellow at the base, broad and blunt wings, and a rather short tail.

When identifying the Water Thick-knee, look for its heavy bill with a yellow base, which is quite distinctive. The wings are broad and blunt, which can be observed when the bird stretches them. The tail is short, which is noticeable when the bird is in flight or when it fans its tail feathers.

The Water Thick-knee is typically found along the edges of lakes, estuaries, and rivers. It also frequents mangroves and some sheltered beaches, often requiring nearby bushes or woodlands for shelter. Its habitat range extends from sea level up to 1,800 m (5,900 ft).

This species enjoys a widespread distribution across sub-Saharan Africa, with sightings reported in countries such as Angola, Botswana, Burkina Faso, and many others, all the way to South Africa.

18-4-2018 CHOBE NAT PARK, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

The Water Thick-knee, also known as the Water Dikkop (Burhinus vermiculatus), presents a striking figure with its 38 to 41 cm (15–16 in) stature and a weight range of 293–320 g (10.3–11.3 oz). This bird is characterized by a robust bill, black with a hint of yellow at the base, broad and blunt wings, and a rather short tail.

When identifying the Water Thick-knee, look for its heavy bill with a yellow base, which is quite distinctive. The wings are broad and blunt, which can be observed when the bird stretches them. The tail is short, which is noticeable when the bird is in flight or when it fans its tail feathers.

The Water Thick-knee is typically found along the edges of lakes, estuaries, and rivers. It also frequents mangroves and some sheltered beaches, often requiring nearby bushes or woodlands for shelter. Its habitat range extends from sea level up to 1,800 m (5,900 ft).

This species enjoys a widespread distribution across sub-Saharan Africa, with sightings reported in countries such as Angola, Botswana, Burkina Faso, and many others, all the way to South Africa.

The Water Thick-knee is a nocturnal terrestrial feeder, often venturing up to 1 km (0.62 mi) away from water to forage. It is known for its unique nesting behavior, often laying its eggs adjacent to or directly on top of Nile crocodile nests, engaging in a symbiotic mutualism with the crocodiles.

The Water Thick-knee is known to be vocal, especially when acting as a sentry for its nest or the crocodile nests it shares. Its calls are used to alert the crocodile of potential threats.

Breeding typically occurs in the dry season or early rainy season. The Water Thick-knee is monogamous, with both parents diligently guarding the nest and brooding the eggs. The nest is a simple scrape in the ground, and the clutch consists of two sandy-yellow eggs. Incubation lasts for 22-25 days, with both parents sharing the responsibility of feeding the young.

The Water Thick-knee can easily be confused with the Spotted Thich-knee.

The diet of the Water Thick-knee includes insects, crustaceans, and mollusks, which it forages for during the night.

The Water Thick-knee is currently listed as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of population decline.

15-4-2018 CHOBE RIVER, NAMIBIA - WATER THICK NEE (Barhinus Vermiculatus) COURTESY OF MRS VALERIE FISHER

The Water Thick-knee, also known as the Water Dikkop (Burhinus vermiculatus), presents a striking figure with its 38 to 41 cm (15–16 in) stature and a weight range of 293–320 g (10.3–11.3 oz). This bird is characterized by a robust bill, black with a hint of yellow at the base, broad and blunt wings, and a rather short tail.

When identifying the Water Thick-knee, look for its heavy bill with a yellow base, which is quite distinctive. The wings are broad and blunt, which can be observed when the bird stretches them. The tail is short, which is noticeable when the bird is in flight or when it fans its tail feathers.

The Water Thick-knee is typically found along the edges of lakes, estuaries, and rivers. It also frequents mangroves and some sheltered beaches, often requiring nearby bushes or woodlands for shelter. Its habitat range extends from sea level up to 1,800 m (5,900 ft).

This species enjoys a widespread distribution across sub-Saharan Africa, with sightings reported in countries such as Angola, Botswana, Burkina Faso, and many others, all the way to South Africa.

17-4-2018 CHOBE RIVER, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

The water thick-knee (Burhinus vermiculatus ), or water dikkop is a species of bird in the thick-knee family Burhinidae. The species is found across sub-Saharan Africa, usually close to water.

The water thick-knee is 38 to 41 cm (15–16 in) and weighs 293–320 g (10.3–11.3 oz). It has a heavy bill that is black with yellow at the base. The wings are broad and blunt and the tail is short.

The water thick-knee has a widespread distribution in sub-Saharan Africa, being found in Angola, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Eswatini, Ivory Coast, Ethiopia, Gabon, Ghana, Kenya, Liberia, Malawi, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Somalia, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe.

Across its range it is found on the edges of lakes, estuaries and rivers, as well as mangroves and also some sheltered beaches. It also needs bushes or nearby woodlands for shelter. It is found from sea-level to 1,800 m (5,900 ft).

The water thick-knee is a terrestrial feeder that forages at night. Although it is typically associated with water it can be found foraging up to 1 km (0.62 mi) from water. It feeds on insects, crustaceans and mollusks.

The water thick-knee generally breeds in the dry season or early rainy season. It is a monogamous breeder. The nest is a simple scrape in sandy or stony ground, usually close to water. The clutch size is two sandy-yellow eggs. Both sexes incubate the eggs for 22-25 days, and both are responsible for feeding the young.

17-4-2018 CHOBE RIVER, BOTSWANA - WATER THICK NEE (Barhinus Vermiculatus)

The Water Thick-knee, also known as the Water Dikkop (Burhinus vermiculatus), presents a striking figure with its 38 to 41 cm (15–16 in) stature and a weight range of 293–320 g (10.3–11.3 oz). This bird is characterized by a robust bill, black with a hint of yellow at the base, broad and blunt wings, and a rather short tail.

When identifying the Water Thick-knee, look for its heavy bill with a yellow base, which is quite distinctive. The wings are broad and blunt, which can be observed when the bird stretches them. The tail is short, which is noticeable when the bird is in flight or when it fans its tail feathers.

The Water Thick-knee is typically found along the edges of lakes, estuaries, and rivers. It also frequents mangroves and some sheltered beaches, often requiring nearby bushes or woodlands for shelter. Its habitat range extends from sea level up to 1,800 m (5,900 ft).

This species enjoys a widespread distribution across sub-Saharan Africa, with sightings reported in countries such as Angola, Botswana, Burkina Faso, and many others, all the way to South Africa.

The Water Thick-knee is a nocturnal terrestrial feeder, often venturing up to 1 km (0.62 mi) away from water to forage. It is known for its unique nesting behavior, often laying its eggs adjacent to or directly on top of Nile crocodile nests, engaging in a symbiotic mutualism with the crocodiles.

The Water Thick-knee is known to be vocal, especially when acting as a sentry for its nest or the crocodile nests it shares. Its calls are used to alert the crocodile of potential threats.

Breeding typically occurs in the dry season or early rainy season. The Water Thick-knee is monogamous, with both parents diligently guarding the nest and brooding the eggs. The nest is a simple scrape in the ground, and the clutch consists of two sandy-yellow eggs. Incubation lasts for 22-25 days, with both parents sharing the responsibility of feeding the young.

The Water Thick-knee can easily be confused with the Spotted Thich-knee.

The diet of the Water Thick-knee includes insects, crustaceans, and mollusks, which it forages for during the night.

The Water Thick-knee is currently listed as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of population decline.

4-4-2018 PHINDA FOREST LODGE, SOUTH AFRICA - WATER THICK NEE (Barhinus Vermiculatus)

The Water Thick-knee, also known as the Water Dikkop (Burhinus vermiculatus), presents a striking figure with its 38 to 41 cm (15–16 in) stature and a weight range of 293–320 g (10.3–11.3 oz). This bird is characterized by a robust bill, black with a hint of yellow at the base, broad and blunt wings, and a rather short tail.

When identifying the Water Thick-knee, look for its heavy bill with a yellow base, which is quite distinctive. The wings are broad and blunt, which can be observed when the bird stretches them. The tail is short, which is noticeable when the bird is in flight or when it fans its tail feathers.

The Water Thick-knee is typically found along the edges of lakes, estuaries, and rivers. It also frequents mangroves and some sheltered beaches, often requiring nearby bushes or woodlands for shelter. Its habitat range extends from sea level up to 1,800 m (5,900 ft).

This species enjoys a widespread distribution across sub-Saharan Africa, with sightings reported in countries such as Angola, Botswana, Burkina Faso, and many others, all the way to South Africa.

The Water Thick-knee is a nocturnal terrestrial feeder, often venturing up to 1 km (0.62 mi) away from water to forage. It is known for its unique nesting behavior, often laying its eggs adjacent to or directly on top of Nile crocodile nests, engaging in a symbiotic mutualism with the crocodiles.

The Water Thick-knee is known to be vocal, especially when acting as a sentry for its nest or the crocodile nests it shares. Its calls are used to alert the crocodile of potential threats.

Breeding typically occurs in the dry season or early rainy season. The Water Thick-knee is monogamous, with both parents diligently guarding the nest and brooding the eggs. The nest is a simple scrape in the ground, and the clutch consists of two sandy-yellow eggs. Incubation lasts for 22-25 days, with both parents sharing the responsibility of feeding the young.

The Water Thick-knee can easily be confused with the Spotted Thich-knee.

The diet of the Water Thick-knee includes insects, crustaceans, and mollusks, which it forages for during the night.

The Water Thick-knee is currently listed as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of population decline.