A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a
flock of usually
insectivorous bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s of different
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
that join each other and move together while foraging.
These are different from feeding aggregations, which are congregations of several species of bird at areas of high food availability.
While it is currently unknown how mixed-species foraging flocks originate, researchers have proposed a few mechanisms for their initiation. Many believe that nuclear species play a vital role in mixed-species flock initiation.
Additionally, the forest structure is hypothesized to play a vital role in these flocks' formation. In
Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
, for example, vocal mimicry by the
greater racket-tailed drongo
The greater racket-tailed drongo (''Dicrurus paradiseus'') is a medium-sized Asian bird which is distinctive in having elongated outer tail feathers with webbing restricted to the tips. They are placed along with other drongos in the family Dic ...
might have a key role in the initiation of mixed-species foraging flocks,
while in parts of the
American
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
tropics packs of foraging
golden-crowned warblers might play the same role.
Composition
Mixed-species foraging flocks tend to form around a "nuclear" species. Researchers believe nuclear species both stimulate the formation of a mixed-species flock and maintain the cohesion between bird species.
They tend to have a disproportionately large influence on the flock. Nuclear species have a few universal qualities. Typically, they are both
generalist
A generalist is a person with a wide array of knowledge on a variety of subjects, useful or not. It may also refer to:
Occupations
* a physician who provides general health care, as opposed to a medical specialist; see also:
** General pract ...
s that employ a
gleaning
Gleaning is the act of collecting leftover crops from farmers' fields after they have been commercially harvested or on fields where it is not economically profitable to harvest. It is a practice described in the Hebrew Bible that became a legall ...
foraging strategy and intraspecifically social birds. "Associate" or "attendant" species are birds that trail the flock only after it has entered their territory. Researchers have shown that these species tend to have a higher fitness following mixed-species foraging flocks. The third class of birds found in mixed-species flocks have been termed "sentinel" species. Unlike nuclear species, sentinels are fly-catching birds that are rarely
gregarious
Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies.
Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...
. Their role is to alert the other birds in the mixed-species flock to the arrival of potential predators.
Benefits
Ecologists generally assume that species in the same ecological niche compete for resources. The formation of mixed-species flocks demonstrates a possible exception to this universal ecological assumption. Instead of competing with one another for limited resources, some bird species who share the same food source can co-exist in mixed-species flocks. In fact, the more similar body size,
taxonomy
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
, and foraging style two bird species are, the more likely they are to be found cooperating in mixed-species flocks Researchers have proposed two primary evolutionary mechanisms to explain the formation of mixed-species flocks. The first mechanistic explanation is that these different bird species cooperate to gain access to more food. Studies have shown that birds in mixed-species flocks are more likely to spot potential food sources, avoid already exploited locations, and drive insects out of hiding. The second mechanistic explanation is that birds join mixed-species flocks to avoid predation. A bird reduces its risk of being eaten when it is surrounded by other birds who can be potential food for the predator instead. Other studies have hypothesized that multi-species flocks form because large groups reduce a predator's ability to single out one prey, while others have hypothesized that multi-species flocks are more likely to spot predators.
Costs
Mixed-species feeding flocks aren’t purely beneficial for their member species. Some bird species suffer a higher cost when joining mixed-species flocks. Studies have shown that some bird species will leave their standard optimal feeding area to travel to a worse foraging location in order to follow the path of a mixed-species flock. Birds may also be forced to change their foraging strategy in order to conform with the flock. Another third proposed cost of mixed-species flocks is an increased risk of
kleptoparasitism
Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when foo ...
.
In the Holarctic
In the North
Temperate Zone
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
, they are typically led by
Paridae
The tits, chickadees, and Titmouse, titmice constitute the Paridae, a large family of small passerine birds which occur mainly in the Northern Hemisphere and Africa. Most were formerly classified in the genus ''Parus''.
Members of this family a ...
(tits and chickadees),
often joined by
nuthatch
The nuthatches () constitute a genus, ''Sitta'', of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs. Mo ...
es,
treecreeper
The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere and sub-Saharan Africa. The family contains eleven species in two genera, ''Certhia'' and ''Salpornis''. Their plumage is ...
s,
woodpecker
Woodpeckers are part of the bird family Picidae, which also includes the piculets, wrynecks, and sapsuckers. Members of this family are found worldwide, except for Australia, New Guinea, New Zealand, Madagascar, and the extreme polar regions. ...
s (such as the
downy woodpecker
The downy woodpecker (''Dryobates pubescens'') is a species of woodpecker, the smallest in North America. Length ranges from . Downy woodpeckers primarily live in forested areas throughout the United States and Canada, with the exception of deser ...
and
lesser spotted woodpecker
The lesser spotted woodpecker (''Dryobates minor'') is a member of the woodpecker family Picidae. It was formerly assigned to the genus ''Dendrocopos'' (sometimes incorrectly spelt as ''Dendrocopus''). Some taxonomic authorities continue to list ...
),
kinglet
A kinglet is a small bird in the family Regulidae. Species in this family were formerly classified with the Old World warblers. "Regulidae" is derived from the Latin word ''regulus'' for "petty king" or prince, and refers to the coloured crowns ...
s, and in North America
Parulidae
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds that make up the family Parulidae and are restricted to the New World. They are not closely related to Old World warblers or Australian warblers. Most ...
(New World "warblers") – all
insect-eating birds. This behavior is particularly common outside the breeding season.
The advantages of this behavior are not certain, but evidence suggests that it confers some safety from predators, especially for the less watchful birds such as
vireos and woodpeckers, and also improves feeding efficiency, perhaps because arthropod prey that flee one bird may be caught by another.
[
]
In the Neotropics
Insectivorous feeding flocks reach their fullest development in tropical forest
Tropical forests (a.k.a. jungle) are forested landscapes in tropical regions: ''i.e.'' land areas approximately bounded by the tropic of Cancer and Capricorn, but possibly affected by other factors such as prevailing winds.
Some tropical fores ...
s, where they are a typical feature of bird life. In the Neotropic
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
Definition
In bioge ...
s the leaders or "core" members may be black-throated shrike-tanagers in southern Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
, or three-striped warbler
The three-striped warbler (''Basileuterus tristriatus'') is a species of bird in the family Parulidae. It was previously considered conspecific with the Tacarcuna warbler and the black-eared warbler. This bird is found in South America from Ven ...
s elsewhere in Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
. In South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, core species may include antbird
The antbirds are a large passerine bird family (biology), family, Thamnophilidae, found across subtropical and tropical Central and South America, from Mexico to Argentina. There are List of antbirds, more than 230 species, known variously as an ...
s such as '' Thamnomanes'', antshrikes, Furnariidae (ovenbirds and woodcreepers) like the buff-fronted foliage-gleaner or the olivaceous woodcreeper
The olivaceous woodcreeper (''Sittasomus griseicapillus'') is a passerine bird of the tropical Americas. It belongs to the true woodcreepers (tribe Dendrocolaptini) of the ovenbird family ( Furnariidae).
It is the only member of the genus ''Sitt ...
, or Parulidae
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds that make up the family Parulidae and are restricted to the New World. They are not closely related to Old World warblers or Australian warblers. Most ...
(New World "warblers") like the golden-crowned warblers.[ In open ]cerrado
The ''Cerrado'' (, ) is a vast ecoregion of tropical savanna in eastern Brazil, particularly in the states of Goiás, Mato Grosso do Sul, Mato Grosso, Tocantins, Minas Gerais, and the Federal District. The core areas of the Cerrado biome are t ...
habitat, it may be white-rumped or white-banded tanagers. Core species often have striking plumage and calls that attract other birds; they are often also known to be very active sentinels, providing warning of would-be predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
s.
But while such easy-to-locate bird species serve as a focal point for flock members, they do not necessarily initiate the flock. In one Neotropic
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
Definition
In bioge ...
mixed flock feeding on swarming termites, it was observed that buff-throated warbling finches were most conspicuous. As this species is not an aerial insectivore, it is unlikely to have actually initiated the flock rather than happening across it and joining in. And while ''Basileuterus
''Basileuterus'' is a genus of New World warblers, best represented in Central and South America. This is one of only two warbler genera that are well represented in the latter continent. Some species formerly considered in this genus are now pl ...
'' species are initiators as well as core species, mixed flocks of '' Tangara'' species – in particular red-necked, brassy-breasted, and green-headed tanagers – often initiate formation of a larger and more diverse feeding flock, of which they are then only a less significant component.[
]Nine-primaried oscine
The nine-primaried oscines is a group of bird families in the suborder Passeri (oscines) of the Passeriformes. The composition of the group has changed since the term was introduced but is now considered to consist of seven major families—Fring ...
s make up much of almost every Neotropical mixed-species feeding flock. Namely, these birds are from families
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...
such as the cardinals
Cardinal or The Cardinal may refer to:
Animals
* Cardinal (bird) or Cardinalidae, a family of North and South American birds
**''Cardinalis'', genus of cardinal in the family Cardinalidae
**''Cardinalis cardinalis'', or northern cardinal, the ...
, Parulidae (New World "warblers"), and in particular Passerellidae
New World sparrows are a group of mainly New World passerine birds, forming the family Passerellidae. They are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns.
Although they share t ...
(American "sparrows") and Thraupidae
The tanagers (singular ) comprise the bird family Thraupidae, in the order Passeriformes. The family has a Neotropical distribution and is the second-largest family of birds. It represents about 4% of all avian species and 12% of the Neotropica ...
(tanagers). Other members of a Neotropic mixed feeding flock may come from most of the local families of smaller diurnal insectivorous birds, and can also include woodpecker, toucan
Toucans (, ) are members of the Neotropical near passerine bird family Ramphastidae. The Ramphastidae are most closely related to the American barbets. They are brightly marked and have large, often colorful bills. The family includes five ge ...
s, and trogon
The trogons and quetzals are birds in the order Trogoniformes which contains only one family, the Trogonidae. The family Trogonidae contains 46 species in seven genera. The fossil record of the trogons dates back 49 million years to the Early E ...
s. Most Furnariidae do not participate in mixed flocks, though there are exceptions such as ''Synallaxis
''Synallaxis'' is a genus of birds in the ovenbird family, Furnariidae. It is one of the most diverse genera in the family and is composed of small birds that inhabit dense undergrowth across tropical and subtropical habitats in the Neotropical ...
'' spinetails and some species of the woodcreeper
The woodcreepers (Dendrocolaptinae) comprise a subfamily of suboscine passerine birds endemic to the Neotropics. They have traditionally been considered a distinct family Dendrocolaptidae, but most authorities now place them as a subfamily of th ...
subfamily
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
– e.g. those mentioned above or the lesser woodcreeper – are common or even "core" members. Among the tyrant flycatcher
The tyrant flycatchers (Tyrannidae) are a family of passerine birds which occur throughout North and South America. They are considered the largest family of birds known to exist in the world, with more than 400 species. They are the most dive ...
s there are also some species joining mixed flocks on a somewhat regular basis, including the sepia-capped flycatcher, eared pygmy tyrant
The eared pygmy tyrant (''Myiornis auricularis'') is a species of bird in the family Tyrannidae. It is found in Brazil, Paraguay and northeastern Argentina. Its natural habitat
In ecology, the term habitat summarises the array of resourc ...
, white-throated spadebill, and Oustalet's tyrannulet.
However, even of commonly participating families not all species join mixed flocks. There are genera such as ''Vireo
The vireos make up a family, Vireonidae, of small to medium-sized passerine birds found in the New World (Canada to Argentina, including Bermuda and the West Indies) and Southeast Asia. "Vireo" is a Latin word referring to a green migratory bir ...
'' in which some species do not join mixed flocks, while others (e.g., the red-eyed vireo
The red-eyed vireo (''Vireo olivaceus'') is a small American songbird. It is somewhat warbler-like but not closely related to the New World warblers (Parulidae). Common across its vast range, this species is not considered threatened by the IUCN. ...
) will even do so in their winter quarters.[ Of the three ]subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
groups of the yellow-rumped warbler, only one (Audubon's warbler
Audubon's warbler (''Setophaga auduboni'') is a small bird of the family Parulidae.
This passerine bird was long known to be closely related to its eastern counterpart, the myrtle warbler, and at various times the two forms have been classed as ...
) typically does. And while the importance of certain Thraupidae in initiating and keeping together mixed flocks has been mentioned already, for example the black-goggled tanager is an opportunistic feeder that will appear at but keep its distance from any disturbance – be it a mixed feeding flock, an army ant
The name army ant (or legionary ant or ''marabunta'') is applied to over 200 ant species in different lineages. Because of their aggressive predatory foraging groups, known as "raids", a huge number of ants forage simultaneously over a limit ...
column or a group of monkey
Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomple ...
s – and pick off prey trying to flee.[
Gnateaters are notable for their absence from these flocks, while swifts and ]swallows
The swallows, martins, and saw-wings, or Hirundinidae, are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The ...
rarely join them, but will if there is for example an ant
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...
or termite swarm. Cotingidae (cotingas) are mainly opportunistic associates which rarely join flocks for long if they do so at all; the same holds true for most Muscicapoidea (mockingbirds and relatives), though some thrushes
The thrushes are a passerine bird family, Turdidae, with a worldwide distribution. The family was once much larger before biologists reclassified the former subfamily Saxicolinae, which includes the chats and European robins, as Old World flycat ...
may participate on more often.[ And though most ]Tityridae
Tityridae is family of suboscine passerine birds found in forest and woodland in the Neotropics. The 45 species in this family were formerly spread over the families Tyrannidae, Pipridae and Cotingidae (''see Taxonomy''). As yet, no widely ac ...
rarely join mixed flocks, becard
A becard is a bird of the genus ''Pachyramphus'' in the family Tityridae.
Taxonomy
The genus ''Pachyramphus'' was introduced in 1839 by the English zoologist George Robert Gray in the volume on birds by John Gould that formed part of Charles Dar ...
s do so regularly.[ ]Tapaculo
The tapaculos or tapacolos are a family, Rhinocryptidae, of small suboscine passerine birds, found mainly in South America and with the highest diversity in the Andean regions. Three species ( Chocó, Tacarcuna, and the silvery-fronted) are ...
s are rarely seen with mixed flocks, though the collared crescentchest
The collared crescentchest (''Melanopareia torquata'') is a species of bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shell ...
, doubtfully assigned to that family, may be a regular member.[ ]Icteridae
Icterids () or New World blackbirds make up a family, the Icteridae (), of small to medium-sized, often colorful, New World passerine birds. Most species have black as a predominant plumage color, often enlivened by yellow, orange, or red. The ...
(grackles and relatives) are also not too often seen to take part in these assemblages, though caciques
A ''cacique'' (Latin American ; ; feminine form: ''cacica'') was a tribal chieftain of the Taíno people, the indigenous inhabitants at European contact of the Bahamas, the Greater Antilles, and the northern Lesser Antilles. The term is a Spa ...
like the golden-winged or red-rumped cacique
The red-rumped cacique (''Cacicus haemorrhous'') is a species of bird in the family Icteridae. It is a species of the Amazon Basin and the Guyanas in northern South America, and is only coastal there in the Guyanas and the Amazon River outlet to ...
join mixed flocks on a somewhat more regular basis.[ ]Cuculiformes
Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separa ...
(cuckoo
Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separ ...
s and allies) are usually absent from mixed feeding flocks, but some – for example, the squirrel cuckoo
The squirrel cuckoo (''Piaya cayana'') is a large and active species of cuckoo found in wooded habitats from northwestern Mexico to northern Argentina and Uruguay, and on Trinidad. Some authorities have split off the western Mexican form as the M ...
– can be encountered not infrequently.[
Some species appear to prefer when certain others are present: '']Cyanolyca
''Cyanolyca'' is a genus of small jays found in humid highland forests in southern Mexico, Central America and the Andes in South America. All are largely blue and have a black mask. They also possess black bills and legs and are skulking birds. ...
'' jay
A jay is a member of a number of species of medium-sized, usually colorful and noisy, passerine birds in the Crow family, Corvidae. The evolutionary relationships between the jays and the magpies are rather complex. For example, the Eurasian m ...
s like to flock with unicolored jay
The unicolored jay (''Aphelocoma unicolor'')
Etymology: ''Aphelocoma'', from Latinized Ancient Greek ''apheles-'' (from ἀφελής-) "simple" + Latin ''coma'' (from Greek ''kome'' κόμη) "hair", in reference to the lack of striped or banded ...
s and the emerald toucanets species complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
. Many Icteridae associate only with related species, but the western subspecies of the yellow-backed oriole associates with jays and the band-backed wren
The band-backed wren (''Campylorhynchus zonatus'') is a small songbird of the wren family.
The band-backed wren is a resident breeding species from south-central Gulf Coast Mexico to northwestern Ecuador. It occurs in five disjunct areas, the c ...
.
Other species participate to varying extents depending on location or altitude – presumably, the different species composition of mixed flocks at varying locations allows these irregular members more or less opportunity to get food. Such species include the grey-hooded flycatcher, or the plain antvireo
The plain antvireo (''Dysithamnus mentalis'') is a passerine bird species in the antbird family (Thamnophilidae). It is a resident breeder in tropical Central and South America.
Taxonomy
The plain antvireo was described by the Dutch zoologist C ...
and the red-crowned ant tanager which are often recorded in lowland flocks but rarely join them at least in some more montane
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...
regions.[
A typical ]Neotropic
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
Definition
In bioge ...
mixed feeding flock moves through the forest at about , with different species foraging in their preferred niches (on the ground, on trunks, in high or low foliage, etc.). Some species follow the flock all day, while others – such as the long-billed gnatwren – join it only as long as it crosses their own territories.
In the Old World tropics
The flocks in the Old World are often much more loosely bonded than in the Neotropics, many being only casual associations lasting the time the flock of core species spends in the attendants' territory. The more stable flocks are observed in tropical Asia, and especially Sri Lanka. Flocks there may number several hundred birds spending the entire day together, and an observer in the rain forest may see virtually no birds except when encountering a flock. For example, as a flock approaches in the Sinharaja Forest Reserve
Sinharaja Forest Reserve is a forest reserve and a biodiversity hotspot in Sri Lanka. It is of international significance and has been designated a Biosphere Reserve and World Heritage Site by UNESCO.
According to International Union for Conser ...
in Sri Lanka, the typical daytime quiet of the jungle is broken by the noisy calls of the orange-billed babbler
The orange-billed babbler (''Argya rufescens'') also known as Ceylon rufous babbler or Sri Lankan rufous babbler is a member of the family Leiothrichidae.
The orange-billed babbler is a resident breeding bird endemic (ecology), endemic to Sri Lan ...
and greater racket-tailed drongo
The greater racket-tailed drongo (''Dicrurus paradiseus'') is a medium-sized Asian bird which is distinctive in having elongated outer tail feathers with webbing restricted to the tips. They are placed along with other drongos in the family Dic ...
, joined by species such as the ashy-headed laughingthrush, Kashmir flycatcher
The Kashmir flycatcher (''Ficedula subrubra'') is a small passerine bird in the Old World flycatcher, flycatcher family Muscicapidae. At one time it was considered to be a subspecies of the red-breasted flycatcher, ''Ficedula parva''.
This is an ...
, and velvet-fronted nuthatch.
A mixed flock in the Cordillera Central of Luzon in the Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
was mainly composed of bar-bellied cuckooshrikes, Philippine fairy-bluebird
The Philippine fairy-bluebird (''Irena cyanogastra'') is a species of bird in the family Irenidae. It is endemic to the Philippines being found in the islands of Luzon, Mindanao, Samar and Bohol.
Its natural habitats are tropical moist lowlan ...
s, and violaceous crows. Luzon hornbill
The Luzon hornbill (''Penelopides manillae''), sometimes called Luzon tarictic hornbill, is a species of hornbill in the family Bucerotidae. It is endemic to forests on Luzon and nearby islands in the northern Philippines. As is the case with al ...
s were also recorded as present. With the crows only joining later and the large hornbills probably only opportunistic attendants rather than core species, it is likely that this flock was started by one of the former species – probably the bold and vocal cuckoo-shrikes rather than the more retiring fairy-bluebirds, which are known to seek out such opportunities to forage.
African rainforests also hold mixed-species flocks, the core species including bulbuls
The bulbuls are members of a family, Pycnonotidae, of medium-sized passerine songbirds, which also includes greenbuls, brownbuls, leafloves, and bristlebills. The family is distributed across most of Africa and into the Middle East, tropical As ...
and sunbirds
Sunbirds and spiderhunters make up the family Nectariniidae of passerine birds. They are small, slender passerines from the Old World, usually with downward-curved bills. Many are brightly coloured, often with iridescent feathers, particularly ...
, and attendants being as diverse as the red-billed dwarf hornbill
The red-billed dwarf hornbill (''Lophoceros camurus'') is a species of hornbill in the family Bucerotidae
Hornbills (Bucerotidae) are a family of bird found in tropical and subtropical Africa, Asia and Melanesia. They are characterized by a ...
and the tit-hylia, the smallest bird of Africa. Drongos
The drongos are a family, Dicruridae, of passerine birds of the Old World tropics. The 30 species in the family are placed in a single genus, ''Dicrurus''.
Drongos are mostly black or dark grey, short-legged birds, with an upright stance whe ...
and paradise-flycatchers are sometimes described as the sentinels of the flock, but they are also known to steal prey from other flock members. Acanthizidae
The Acanthizidae—known as Australian warblers—are a family of passerine birds which includes gerygones, the thornbills '' Acanthiza'', and the scrubwrens of '' Sericornis''. The Acanthizidae family consists of small to medium passerine birds, ...
are typical core members in New Guinea and Australia; in Australia, fairy-wrens are also significant. The core species are joined by birds of other families such as minivet
The minivets are passerine birds belonging to the genus ''Pericrocotus'' in the cuckooshrike family Campephagidae. There are about 15 species, occurring mainly in forests in southern and eastern Asia. They are fairly small, slender birds with lon ...
s.
Notes
References
*
External links
*
{{DEFAULTSORT:Mixed-Species Foraging Flock
Zoology
Bird behavior
Ornithology
Birds