Cattleya of Central and South America

Cattleya includes 40-65 species of epiphytic herbs from Central and South America. They are found from high-altitude cloud forests to coastal woodlands from Costa Rica to South Argentina. The genus is closely allied to Epidendrum. Cattleyas are the quintessential orchids to most people, commonly used in corsages. Leaves are usually oblong and stiff, attached to the ends of stalked pseudobulbs. Pseudobulbs are short, swollen stems that store water; they are typical of orchids that grow in seasonally moist/dry climates. New growth arises from the base of the previous pseudobulb (sympodial). Flowers have spreading tepals and a simple or lobed, often fringed or ruffled lip.

Cattleyas are divided horticulturally into 2 groups. Those in the bifoliate group have 2, or occasionally 3, leaves at the end of slender pseudobulbs. Flowers are small to medium, born in clusters. The unifoliate, or labiate cattleyas, have a single leaf at the end of a stout pseudobulb and 1-3 large flowers with showy lips. This latter group is the basis of most hybrids. In Costa Rica, certain orchids are sometimes so prolific, even growing between roof tiles, that they are considered pests. Cattleyas readily hybridize with a number of related genera. Intergeneric hybrid names are usually abbreviated; for example, LC is an abbreviation for the group xLaeliocattleya (Laelia x Cattleya).

Cattleya bowringiana - Synonym: C skinneri var. bowringiana. Belize, Guatemala, Honduras. Epiphytic herb; zones 10-11. Blooms fall. Regular moisture and humidity, dry when cool. Mount on tree-fern slab or limb, pot in orchid mix. Bright broken light. Flowers: to 3 in. wide, magenta, throat with white spot. Leaves: bifoliate, oblong, to 8 in.; pseudobulb elongated, stem like, to about 1 ft. long. Produces massive clumps. This species is similar but more prolific and with smaller flowers than C. skinneri, which blooms in late winter and spring. Spectacular when massed on stumps or sturdy limbs. Forgiving and pest resistant.

Cattleya xguatemalensis Natural hybrid (Central America), - C aurantiaca x C. skinneri. Epiphytic herb; zones 10-11. Blooms late fall, winter. Regular moisture and humidity; dry when cool. Mount on tree-fern slab or limb, pot in orchid mix. Bright broken light. Flowers: pinkish lavender to pinkish orange, lip tubular at base, tip red, throat orange; in many-flowered clusters. Leaves: bifoliate, oblong, to 6 in.; pseudobulb cylindrical, stem-like. A natural hybrid resembling the C. skinneri parent vegetatively. Cattleya percivaliana

CATTLEYA - Synonym: C. labiata var. percivaliana. Venezuela. Epiphytic or lithophytic herb; zones 10-11. Blooms winter. Moist and humid, dry when cool. Mount on tree-fern slab or limb, pot in orchid mix. Full sun to bright broken light. Flowers: tepals pink-lavender, to 5 in. wide, lip deep magenta at the tip, throat streaked with violet and orange; margins ruffled.

MARSH OWL "Asio capensis"

 IDENTIFICATION A medium-sized owl (29–38cm), generally disc. Upperparts sometimes with very fine speckles. Facial disc distinctly rimmed. A Blackish-brown area surrounds dark brown eyes. Erectile ear-tufts very tiny and mostly invisible, set near the center of the forehead. Wings and tail barred tawny and dark brown. In-flight shows prominent dark wrist-patch, visible from above and below; upper primaries with rather plain tawny bases. Below, diffusely vermiculated dusky on paler brown, appearing rather plain (birds from Madagascar more finely barred below). Tarsi feathered; toes partly covered with short plumes; outermost tips rather bare.

Similar species Short-eared Owl is generally pale yellowish-brown with distinct dusky streaking, especially on underparts; eyes pale yellow. Long-eared, Abyssinian Long-eared and Madagascar Long-eared Owls have prominent ear-tufts, yellow to orange eyes, and boldly patterned underparts. Tawny Owl is more boldly patterned, has a broad, rounded head and large blackish-brown eyes (lacks blackish mask), and has whitish outer webs to scapulars. African Wood Owl has barred underparts and a whitish scapular stripe. Eagle owls (Bubo) are larger, with prominent ear-tufts. African fishing owls have bare tarsi and toes. African Grass Owl is larger, dark brown above and pale below, has heart-shaped facial disc with relatively small, blackish eyes and relatively long legs with bristled toes.

VOCALISATIONS Little studied. Very different from all other members of this genus. Most common is a hoarse, grating call, uttered when perched or when circling overhead and clapping wings in the display, sounding like the noise produced by breaking a dry branch by bending it slowly, kerrrrrrrr; being repeated at variable intervals. This vocalization might be the territorial song, often accompanying wing-clapping. Also gives sequences of croaking, raven-like calls on the wing: quarrk-quarrk-quarrk.

Female utters similar but higher-pitched and softer calls. These vocalizations might perhaps express aggression against intruders. Female and fledged young utter far-carrying, wailing hisses with ventriloquially character: shooeeh. If disturbed at the nest, both sexes may fly around with croaking calls and high mewing screams. DISTRIBUTION Africa and Madagascar. An isolated population exists in extreme NW Africa in Morocco. Patchily earth-brown, with a rounded head and distinct pale facial distributed south of the Sahara from Senegambia and Ethiopia to the Cape.

MOVEMENTS In general resident, but partly nomadic within sub-Saharan Africa and an intra-African migrant. Stragglers have been observed in S Iberian Peninsula and The Canary Islands. Displacements are generally caused by responses to food abundance (e.g. rodent plagues) or shortage or are the result of bush fires, floods, etc.

HABITAT Open country from coastal marshes to savanna, with or without scattered trees and bushes; also, inland marshes, moors, and montane grassland, from sea-level up to c.3000m. Avoids extensive long grass, but favors terrain with short vegetation and some patches of long grass or weeds. Locally in rice fields and drainage strips in wooded savanna (‘dambos’), sometimes open areas near or even in human settlements. Absent from forested areas, rocky landscapes, and deserts.

DESCRIPTION A. c. capensis Adult Sexes alike, but males generally paler than females; individually variable in tone. Facial disc pale buff, with the dark brown area around eyes; distinct facial rim dark brown with buff speckles. Ear-tufts earth-brown, very tiny and barely visible, set near the center of the forehead. Upperparts plain earth-brown, crown, and nape finely vermiculated buff, upper tail-coverts barred buff. Primaries with rather plain, pale tawny-buff bases, contrasting with a dusky patch at the wrist; rest of flight feathers barred dark brown and tawny-buff. Tail dark brown, barred pale buff, with whitish tip. Underparts brown, finely vermiculated buff, becoming more uniform pale buff on thighs, belly, and under tail-coverts.

Underwing-coverts buff with dark brown wrist patch, very conspicuous in flight. Tarsi feathered pale tawny-buff; toes covered with pale buffish plumes, leaving tips bare. Juvenile Downy chick covered with buffish down, has pink skin, blackish bill, and pink toes. Mesoptile buff barred brown above; facial disc darker than an adult, with the marked blackish rim. After molt (at c.10 weeks), distinguishable from an adult by buff tips to scapulars and lower back feathers. Bare parts Eyes dark brown. Cere grey-brown. Bill blackish-horn. Bare parts of toes dark brown. Claws blackish.

MEASUREMENTS AND WEIGHT - Total length 31–38cm. Wing 284–380mm, tail 132–186mm. Weight 225–485g.

GEOGRAPHICAL VARIATION - We distinguish three subspecies. A. c. capensis (A. Smith, 1834). Africa south of Sahara. See Description. Wing 285–330mm, tail 132–163mm. Weight: males 243–340g, females 305–376g. A. c. tingitanus (Loche, 1867). Morocco, rarely straggling to S Iberia and Canary Islands. Darker than nominate, with rufous wash and some small whitish markings, especially below. Wing 284–312mm, tail 132–153mm. Weight 310–350g. A. c. hova Stresemann, 1922. Madagascar. Largest subspecies. Underparts more barred and spotted; pale parts of primaries paler. Bill and talons are more powerful than in other races. Wing 322–380mm, tail 176–186mm.

Weight of one male 485g. HABITS Occurs singly or in pairs, sometimes in larger numbers (especially outside breeding season). Mostly crepuscular and nocturnal, but sometimes also active during cloudy days. By day, normally roosts on the ground in a hollow among grass or other vegetation. At dusk or by night, often perches on fence posts, stumps, or tops of bushes watching for prey. May be aggressive near the nest or feign injury in order to distract potential enemies. Flight very similar to that of a harrier Circus.

FOOD - Depends largely on availability. Normally small rodents form the major part of its diet, but sometimes small birds may be predominant; also takes other small vertebrates and insects. Prey includes mice, voles, rats, shrews, young hares, bats, birds up to the size of small ducks and doves, frogs, lizards, scorpions, beetles, grasshoppers, termite alates, etc. Most prey is captured by flying close to the ground with slow but powerful wingbeats, interspersed with fast swerves and hovering, before dropping on to victim; sometimes hawks flying insects, even those attracted by streetlamps in urban areas.

BREEDING - Monogamous and territorial. Sometimes nests in loose colonies. Territories are normally 0.8–2km2 in size, sometimes smaller when the population is denser; in South Africa, nests have been found c.75m apart. Hunting areas of neighboring pairs may overlap. Male claims territory by circling over it, clapping wings and croaking; during courtship, pair-members often fly in wide circles at dusk and on moonlit nights, with wing-clapping and croaking calls (song?). Copulation normally occurs on the ground. A hollow within a patch of tall grass or weeds, often beside a bush and with an ‘entrance tunnel’ from one side, is used for nesting, vegetation often being pulled over by the female to form a canopy. The depression itself is lined with some dry leaves to form a pad (this is probably done by the female but needs confirmation).

In Morocco, a nest was found c.4m above ground in an old corvid nest in a bush, the only known case of a nest not at ground level. Locally, nests in close vicinity to African Grass Owl; in one case the nests were only 20m apart. Nesting normally occurs towards the end of the wet season. The female lays 2–6 (normally three) white eggs (40 x 34.1mm), at intervals of about two days, and incubates alone, starting with the first egg. During incubation she is fed by her mate, who brings food to the nest in its talons, calling as he approaches. He lands at the nest, walks in through the tunnel, and delivers food mostly from bill to bill, but the female sometimes snatches it from his talons. If food is abundant, items may be cached at the nest by the female, or in deposits outside by the male. Incubation lasts 27–28 days for each egg.

Chicks’ eyes open at seven days, and by ten days the facial disc is well developed, already showing characteristic blackish mask and black rim. Up to this age, they are regularly brooded by the female. At 18 days (sometimes as early as 10–14 days), when young still appear downy, they begin to leave the nest and scatter in the surrounding vegetation. An adult defended its chicks by chasing off an African Marsh Harrier Circus ranivorus. Adults carry food directly to their offspring, the young indicating their position by calls and trampling movements. When 30 days old, young have acquired most contour feathers. By 70 days they are fully feathered but are able to fly earlier, by 29–35 days. Both parents care for them for some time before they become independent.

STATUS AND CONSERVATION Uncertain. The NW Moroccan population is declining and endangered by habitat loss and disturbance. South of the Sahara, locally common in years with abundant food. Is affected by bush fires, floods, overgrazing by cattle, and the use of pesticides. Some are killed by road traffic or by entanglement in barbed wire fences.

REMARKS This species, the ecological counterpart in Africa of the Short-eared Owl has been assumed to be a close relative of the latter, but we believe the similarities in ecology and external appearance are due to convergence and not to the relationship. Their totally different vocalizations support this view. In any case, it would be unwise to consider the two as comprising superspecies, and certainly not as members of the same species. The Marsh Owl’s vocalizations, behavior, reproductive biology, taxonomy, and DNA relationships need further study.

Great cormorant

 Great cormorant

Phalacrocorax carbo

TAXONOMY

Pelecanus carbo Linnaeus, 1758, Europe. Six subspecies.

OTHER COMMON NAMES

English: Black cormorant, white-breasted cormorant; French: Grand Cormoran; German: Kormoran; Spanish: Cormorلn

Grande.

PHYSICAL CHARACTERISTICS

This largest species of cormorant has a body length of about 37 in (93 cm), with a pale-yellow bill, pale yellow cheek pouch

bordered by a white throat, glossy blackish plumage, black legs and feet, and males somewhat larger than females (males: 5.1

lb (2.3 kg); females: 4.2 lb (1.9 kg).

DISTRIBUTION

A very widespread species in temperate regions of the world, occurring locally in the Northwest Atlantic of North America,

more widely through Eurasia, and in parts of Southeast Asia, Africa, and Australia. They generally winter near their breeding

grounds.

HABITAT

Nests on sea cliffs feed in coastal waters.

BEHAVIOR

A highly social species that breed in colonies and aggregates in flocks. Like all cormorants, it catches fish by underwater pursuit.

FEEDING ECOLOGY AND DIET

Feeds on small fish, crustaceans, and squid.

REPRODUCTIVE BIOLOGY

Normally, Great cormorant lays 3 to 4 eggs in a crude stick-nest on a cliff ledge. However, both sexes sharing the incubation for the 26 to 32 days and rearing of the chicks.

CONSERVATION STATUS

Not threatened. Rather abundant over much of its range.

SIGNIFICANCE TO HUMANS

Not of great importance to humans over most of the range; however, in Japan, this is one of two species (the other is the Japanese cormorant, Phalacrocorax capillatus) trained by human fishers to help them catch fish.

Newton’s Parakeet "Psittacula exsul" (A. Newton)

 OTHER NAME - Rodrigues Parakeet.

DESCRIPTION Length 40 cm.

Newton’s Parakeet Presumably green and blue morphs existed, and mention is made in an early account by Julien Tafforet of a red alar patch being present in the adult male of the green morph. Only two specimens survive, and both are of the blue morph. ADULT MALE General plumage greenish-blue with a greyish cast, paler on underparts; head noticeably darker and without greyish suffusion; fine black line from cere to eyes; chin black; broad black stripe across lower cheeks to sides of the neck, then becoming narrow and continuing up to nape; lower back and rump paler, lighter blue; primaries deep greenish-blue; tail dark greenish-blue above, greyish underside; upper mandible red, lower mandible black; iris yellow (Vandorous); legs grey. 1 specimen: wing 199 mm, tail 207 mm (abraded); exp. cul. 25 mm, tars. 22 mm. ADULT FEMALE Very faint black line on the forehead; black stripes not extending beyond sides of neck; crown suffused grey; upper mandible black. 1 specimen (type): wing 192 mm, tail 212 mm, exp. cul. 24 mm, tars. 23 mm. JUVENILES Undescribed. DISTRIBUTION Formerly occurred on Rodrigues, in the The Mascarene Islands.

 

STATUS The last records of Newton’s Parakeet were made in the 1870s, and presumably, it became extinct at about that time. Only two specimens were collected, the first being a female, which was collected in 1871 by George Jenner, the then magistrate on the island. This specimen was preserved in alcohol and given to Edward Newton, a colonial administrator on Mauritius, who in turn sent it to his brother, and it was used by Alfred Newton to describe the species (Newton and Newton 1876). The second specimen, a male, was shot by a local resident William Vandorous on 14 August 1875 and given to the assistant colonial secretary William Caldwell, who in turn forwarded it to Edward Newton. Caldwell remarked that he had seen several birds but could not get near one. Henry Slater, a naturalist who stayed on the island for three months in 1874, reported to Newton that on 30 September in that year he saw a single bird in a forest towards the southwestern end of the island (in Newton 1875).

It has been postulated that the male collected by Vandorous may have been the same bird seen by Slater in the previous year.

Hume (2007) documents account from early visitors to Rodrigues and note that although Newton’s Parakeets survived until the 1870s, they were in decline from the 1760s. François Leguat reported that they were abundant at the time of his stay on the island between 1691 and 1692: There is an abundance of green and blew Parrot's, they are of a middling and equal bigness; when they are young, their Flesh is as good as young Pigeons. Hunting and fishing were so easy for us, that it took away from the Pleasure. We often delighted ourselves in teaching the Parrots to speak, there being vast numbers of them. We carried one to Maurice Isle, which talked French and Flemish. A live bird was received by the naturalist Philibert Commersen on Mauritius during the 1770s, where it was described as a long-tailed, greyish-blue parrot with a black collar (in Oustalet 1897).

Hume notes that the parrots were still common when Julien Tafforet was on Rodrigues in 1726 but had become rare by the time of a visit in 1761 by Abbé Alexandre Pingré, a French astronomer who had come to monitor the transit of Venus, and he referred to their continued presence on the southern islets (translation by Hume): On the 19th at Isle Mombrani, the multitude of grey terns on our side served exactly as a parasol; they fly about our heads, in the manner more or less to ease the heat of the sun. In an additional premium to this, there were tropic birds and their eggs. There are also some frigates, some tratras, some perruches. After the visit by Pingré, there was severe deforestation on the island and an increase in numbers of free-roaming livestock. In 1843, a government surveyor Thomas Corby was sent to Rodrigues to ascertain the suitability of the land to support cattle and he noted that the western side of the island, although severely deforested, contained the best stands of palms and Pandanus screwpines. Corby also referred to the presence of many wild bullocks, pigs, great flights of guinea fowl and green parrots, indicating that Newton’s Parakeets remained fairly numerous, but they had become extremely scarce by 1871 when the first the specimen was received by Alfred Newton.

There were no records after the second specimen was collected in 1875, and Hume suggests that the last few survivors may have been wiped out by a devastating series of cyclones in the following year. HABITATS Newton’s Parakeets presumably frequented native forest, and extensive destruction of this habitat was a major factor in their decline and subsequent extinction. HABITS Leguat commented on the partiality of Newton’s Parakeets to the nuts of bois d’olive Cassine orientale and made mention of the bois du buis Fernelia buxifolia being a food tree for Newton’s Parakeets and for Leguat’s Parrot Necropsittacus rodericanus (in Hume 2007). Nothing is known of habits of Newton’s Parakeets, though they probably were similar to the habits of Mauritius Parakeets. SPECIMENS AVAILABLE Both specimens (18/Psi/67/h/1

---

 type and 18/Psi/67/h/2 [1]) are held in the Museum of Zoology at Cambridge University, UK. Mascarinus Lesson, Traité d’Orn., livr. 3, 1830, p. 188. Type, by tautonymy, Mascarinus madagascarensis Lesson = Psittacus mascarin Linnaeus.

The extinct species belonging to this monotypic genus was a midsized parrot with a large red bill and a moderately long, broadly rounded tail. Traditionally, it has been associated with the Psittaculini and, apart from plumage coloration, it resembles the Tanygnathus parrots from Southeast Asia. Alternatively, it has at times been linked with Coracopsis from Madagascar and the Comoros Archipelago, probably because of a the similarity in the brown plumage coloration, and it has been noted that Coracopsis and Mascarinus are the only parrots that naturally lack psittacin in their plumage (in Hume and van Grouw 2014). An extraordinary finding from molecular analyses that a cytochrome b sequence from mitochondrial DNA of Mascarinus is embedded in Coracopsis has been questioned on the basis that the mitochondrial DNA was extracted from the damaged type specimen (MNHN 211) and alternative hypotheses concerning the placement of Mascarinus were not considered (see Kundu et al. 2012; Joseph et al. 2012).

Molecular analyses of DNA extracted from the only other specimen (NMW 50.688) indicates that the previously obtained cytochrome b sequence probably is an artificial composite of partial sequences from two other parrot species and that Mascarinus is indeed part of the Psittacula diversification, placed close to P. eupatria and P. wardi (Podsiadlowski et al. 2017). I strongly support this finding and am of the opinion that all three extinct monotypic genera from the Mascarene Islands – Mascarinus, Necropsittacus, and Lophopsittacus – can be placed in Psittaculini. Mascarinus formerly occurred on Réunion, and possibly on Mauritius, in the Mascarene Islands. 

Gray butcherbird – “Cracticus torquatus”

 Gray butcherbird – “Cracticus torquatus”

SUBFAMILY - Cracticinae

TAXONOMY

Lanius torquatus Latham, 1802, Port Jackson (Sydney), Australia. Three, possibly four subspecies; one large and dark with reduced white in wing in Tasmania (Cracticus torquatus cinereus), another small and dark with reduced white in wing in coastal southeastern Australia between the New South Wales-Queensland border and Melbourne (nominate torquatus), and a third (that may comprise east and west forms) small and paler with extensive white in wing throughout southern and inland Australia from the west coast to coastal Queensland south of Cape York Peninsula (C. t. leucopterus). The gray butcherbird forms a superspecies with the silver-backed butcherbird (C. argenteus) of northwestern Australia and the black-backed butcherbird (C. mentalis) of Cape York Peninsula and dry sectors of southeastern New Guinea.

OTHER COMMON NAMES

French: Cassican à collier;

German: Graurücken-Würgatzel;

Spanish: Pájaro Matarife Gris.

DESCRIPTION

Primary and tall secondary rainforests, particularly along edges and around openings such as tree falls, stream edges, and road cuttings. Densities have been estimated at two birds per 25 acres (10 ha) in suitable habitat. Widely but sparsely distributed year-round residents; solitary, in loose pairs or small family groups of three to five. Live mostly on top of forest canopies, perching upright and motionless for long periods on exposed vantage perches, from which they fly out in extended sallies. From perches and in flight, birds utter distinctive territorial and advertising calls at regular intervals; calls are a series of three or so well spaced mechanical double clicks over four to five seconds. At perches, the singer throws its head violently up and down at each click. Other calls include a harsh monarch-like wheeeit, possibly in warning or agitation, and a seldom-heard wrenlike twittering.

FEEDING ECOLOGY AND DIET

Apparently wholly insectivorous, birds capture food in the air and from the surface of foliage with the bill on sallying flights. Most foraging is done in and above the forest canopy but sometimes extends to lower strata. Food, including dragonflies, beetles, grasshoppers, and other flying insects, is swallowed whole at a perch, without much beating.

REPRODUCTIVE BIOLOGY

Data lacking on timing and duration of events and respective parental contribution. Nests are small, compact cups of twigs and rootlets built-in often exposed positions in horizontal tree forks at the ends of branchlets at 20–115 ft (6–35 m) above the ground; and eggs, usually one per clutch, are cream to pale buff, with a ring of black-brown spotting at the larger end.

PHYSICAL CHARACTERISTICS

10–12 in (25–30 cm); 2.8–4.0 oz (80–110 g). Medium-sized bull-headed bird with tapered body and black-, gray-, and white-patterned plumage. Head black with white lore spot (between eye and upper bill) and collar, back gray, rump white, tail and wings black with white tips and stripes respectively, and undersurface uniformly grayish white. Eyes dark brown, feet gray, and bills bicolored, with a black tip and gray-white base. Females are usually grayer-breasted and shorter billed than males. Juveniles dull-gray-billed and dully patterned, with dusky-olive and speckled upper parts and yellowish underparts.

DISTRIBUTION

Most of southern and inland Australia north to 20°S, including Tasmania but excluding treeless deserts.

HABITAT

Closed woodland and open forest of eucalypts and acacias, including mallee (Eucalyptus) and mulga (Acacia) scrubs, where the space between tree crowns is about the size of the crowns themselves. Densities range from one bird to about 12 to 49 acres (5–20 ha) in suitable habitat.

BEHAVIOR

Retiring and solitary, in pairs or small family groups, gray butcherbirds live in the mid-and upper strata of trees, spending much of their time perching still and coming to ground only to pounce on prey. They are sedentary, with pairs holding the same territory, 20–99 acres (8–40 ha), year-round, with a larger home range. Both male and female duet antiphonally in songs of fluted whistles and ringing caws, which are also given in alarm and aggression.

FEEDING ECOLOGY AND DIET

Gray butcherbirds are raptorial perch-pouncers, watching from tree perches at 6.5–40 ft (2–12 m) up, then swooping down to ground or branches to snap up prey, which is mostly insects but also small birds, nestlings, reptiles, and mice. Fruit also contributes to the diet. Food is carried back to perch, wedged in crannies or forks and torn apart with the bill for eating; the small weak feet are not used for tethering prey.

REPRODUCTIVE BIOLOGY

Monogamous, forming pair bonds in breeding territories reinforced by much duetting during early breeding. Gray butcherbirds breed mostly between July and August and December and January throughout their range. The nest, a rough but tight cup of twigs lined with finer, often reddish fiber, is placed in upright forks in outer foliage at 10–50 ft (3–15 m) up and takes about four weeks to build. Eggs, in clutches of three to five, are 1.20–1.25 x 0.85–0.95 in (30–32 x 22–24 mm), brownish-green, and finely freckled in red browns, often in a zone around the larger end; they hatch in 22–24 days. The Female builds the nest and incubates unaided, while the male defends the territory. He may assist her in feeding young, which fledge around four weeks. Usually, only one brood is reared per year.

CONSERVATION STATUS

Not threatened, although many populations have declined locally because of habitat clearing and alienation.

SIGNIFICANCE TO HUMANS

Some local populations frequent camping sites, feeding on scraps and garbage thrown out by campers. They are called commensals in such circumstances because they benefit from a close association with humans.