Flock Formation Research Articles

Flock formation and the role of plumage colouration in Ardeidae

It has been hypothesized that white plumage facilitates flock formation in Ardeidae. We conducted four experiments using decoys to test factors involved in attracting wading birds to a specific pond. The first three experiments tested the effects of plumage colouration, flock size, and species-specific decoys on flock formation. The fourth experiment examined intraspecific differences in flock choice between the two colour morphs of the reddish egret, Egretta rufescens (Gmelin, 1789). Wading birds landed at flocks of decoys more often than single or no decoys (P < 0.001) but exhibited no overall attraction to white plumage (P > 0.05). White-plumaged species were attracted to white decoys (P < 0.001) and dark-plumaged species were attracted to dark decoys (P < 0.001). Snowy egrets (E. thula (Molina, 1782)), great egrets (Ardea alba L., 1758), and little blue herons (E. caerulea (L., 1758)) landed more often at ponds that contained decoys resembling conspecifics. At the intraspecific level, all observed reddish egrets selected flocks with like-plumaged decoys. Our results suggest that plumage colouration is an attractant for species with similar plumage, but white plumage is not an attractant for all wading bird species. White plumage may facilitate flock formation in certain species but does not serve as a universal attractant for wading birds of varying plumage colouration and size.

The species flocks of East African cichlid fishes: recent advances in molecular phylogenetics and population genetics.

With more than 3,000 species, the fish family Cichlidae is one of the most species-rich families of vertebrates. Cichlids occur in southern and central America, Africa, Madagascar, and India. The hotspot of their biodiversity is East Africa, where they form adaptive radiations composed of hundreds of endemic species in several lakes of various sizes and ages. The unparalleled species richness of East African cichlids has been something of a conundrum for evolutionary biologists and ecologists, since it has been in doubt whether these hundreds of species arose by allopatric speciation or whether it is necessary to invoke somewhat less traditional models of speciation, such as micro-allopatric, peripatric, or even sympatric speciation or evolution through sexual selection mediated by female choice. Ernst Mayr's analyses of these evolutionary uniquely diverse species assemblages have contributed to a more direct approach to this problem and have led to a deeper understanding of the patterns and processes that caused the formation of these huge groups of species. We review here recent molecular data on population differentiation and phylogenetics, which have helped to unravel, to some extent, the patterns and processes that led to the formation and ecological maintenance of cichlid species flocks. It is becoming apparent that sexually selected traits do play an important role in speciation in micro-allopatric or even sympatric settings. Species richness seems to be roughly correlated with the surface area, but not the age, of the lakes. We observe that the oldest lineages of a species flock of cichlids are often less species-rich and live in the open water or deepwater habitats. While the species flocks of the Lake Malawai and the Lake Victoria areas were shown to be monophyletic, the cichlid assemblage of Lake Tanganyika seems to consist of several independent species flocks. Cichlids emerge as an evolutionary model system in which many fundamental questions in evolution and ecology can be tested successfully, yet for other fish species flocks the relative importance of alternative mechanisms of speciation is likely to differ from that in cichlid fish.

Selection for synchronous breeding in the European starling

Colonial birds often demonstrate considerable breeding synchrony. In southern Sweden the semi‐colonial European starling initiated the vast majority of clutches within one week. Laying dates were positively skewed so that many birds initiated clutches at similar dates early in the season. Breeding was further synchronised by a particularly strong clutch‐size reduction equivalent to one third of an egg per day during the first part of the breeding season. The decline in clutch size with season also held true for separate age‐classes of females, for individual females laying at different times at different years and for individual females laying at different times the same year. Trends in breeding success during nestling rearing were unlikely to explain the high degree of breeding synchrony or the seasonal decline in clutch size; nestling survival and growth were weakly related or unrelated to reproductive timing. In contrast recruitment success of fledged offspring declined sharply with season. Even within the synchronous laying period, defined as clutches initiated during the first week each year, local recruitment success declined. It is suggested that the early seasonal decline is caused by selection for synchronous fledging permitting the immediate formation of flocks after fledging, whereas the late seasonal trends may be caused by either population differences in female quality or deteriorating conditions for raising young.

Winter flocking behaviour of speckled warblers and the Allee effect

The aggregation of individuals into foraging flocks is one behavioural trait that, if disrupted, can cause the Allee effect, which is a slowing in population growth at low density or small population size, and this can greatly increase the risk of extinction. Here, I describe intraspecific flocking behaviour of a colour-banded population of speckled warblers, Chthonicola sagittata, a species that has declined across a large part of its range in the fragmented temperate woodlands of Australia. I make predictions about the context in which the Allee effect might be expressed and the consequences for the viability of populations living in small habitat remnants. Speckled warblers lived in discrete, stable social groups throughout winter, the nucleus of which was the residents from one or more adjacent breeding territories. The timing and mode of flock formation and the size of flocks varied between two winters, apparently in response to the severity of conditions; thus flocking probably facilitates increased foraging efficiency and predator detection, potentially leading to increased survival in harsh conditions. Because flock territories were up to 30 ha each, and larger territories are likely, birds living in remnants smaller than 40 ha may suffer increased mortality if there are too few birds available to form flocks of an appropriate size to facilitate the benefits of grouping when conditions are most extreme. Further, in small remnants where survival is reduced, dominance behaviour and male–male competition may act to compound the Allee effect by reducing reproductive success. Regardless of these predictions, speckled warbler populations may only be viable in remnants that are large enough to support multiple flocks, to enable rapid recruitment to breeding vacancies and thus provide adequate numbers of birds for flocking.

Anatomy and systematic affinity ofStanleya neritinoides(Smith, 1880), an enigmatic member of the thalassoid gastropod species flock in Lake Tanganyika, East Africa (Cerithioidea, Paludomidae)

AbstractThe radiation of gastropods in Lake Tanganyika is an ideal system for testing competing hypotheses of species flock formation. Yet, much of the basic biology of these species remains unknown. In an ongoing effort to understand the evolution of Tanganyikan gastropods, we here describeStanleya neritinoides. Alcohol‐preserved material of the soft parts is rare, consequently, the systematic position of the species, and a repeated suggested affinity toTanganyicia rufofilosa, have been based primarily on features of the shell. However, features of the radula and operculum are unique and do not suggest an affinity to any other Tanganyikan species. Thus,S. neritinoideshas remained a particularly poorly known and enigmatic member of the species flock. This investigation confirmed that several aspects of internal and external anatomy are shared betweenS. neritinoides,T. rufofilosa, and other Tanganyikan gastropods, but thatS. neritinoidesis unique in features of the radula and seminal receptacle. Moreover,S. neritinoidesdiffers fromT. rufofilosain features of the foregut, midgut, hindgut, kidney, nervous system, reproductive system and reproductive strategy. These new data are inconsistent with an interpretation of identity ofStanleyaandTanganyicia.In addition, given the pervasive differences between the two, a sister‐group relationship between the two is unlikely. More precise systematic placement ofS. neritinoidesawaits the establishment of a phylogenetic framework for all Tanganyikan gastropods.

The energetics of barnacle geese ( Branta leucopsis) flying in captive and wild conditions

Experimental data on the relationship between mean heart rate ( f H) and mean rate of oxygen consumption ( V ̇ o 2) of captive barnacle geese during flights in a wind tunnel are assessed in terms of their capacity to predict the typical V ̇ o 2 of wild barnacle geese, based on the recordings of their f H, while undertaking autumn migratory flights between Spitsbergen (78°N) and Caerlaverock, Scotland (55°N). A significant linear relationship has been demonstrated between the f H and simultaneously recorded V ̇ o 2 of a single barnacle goose (B–B) flying in the wind tunnel ( V ̇ o 2=1.42 f H−304, r 2=0.82, P<0.001, N=12 flights). Data recorded from three additional geese ( N=4 flights), lay within the 95% prediction intervals of the relationship for goose B–B. When these geese (mean body mass=2.06 kg, n=4) were flown in the wind tunnel (WT) without the mask, they had a mean f H of 451±23 beats min −1, yielding an estimate for V ̇ o 2 of 336±33 ml min −1. However, f H has also been recorded from wild barnacle geese (mean migratory f H of 253 beats min −1), and substitution of this value into the above calibration equation results in an unrealistically low value for mean migratory V ̇ o 2 of only 55 ml min −1. Various factors, such as differences in heart mass, selective tissue perfusion, environmental temperature and flock formation, which might account for some of the difference in f H between the captive and wild geese are discussed. Comparison with other WT studies shows that inter-species minimum mass-specific V ̇ o 2 declines with increasing body mass ( M b; range 0.035–2.8 kg) as 173 M b −0.224, r 2=0.848.

Nested patterns of species distribution and winter flock occurrence of insectivorous birds in a fragmented landscape

The goal of this paper is to evaluate whether the probabilities of aggregating in flocks are dependent on the patterns of species distribution across the landscape. I analyzed winter species distribution and flock occurrence (flock formation in a given fragment) at the community and individual species levels of a guild of small insectivorous birds in a fragmented landscape. Species distributed following a nested pattern, which was mainly affected by fragment size. Flock occurrence (single- plus mixed-species flocks) followed a nested pattern, such that the probability of joining flocks was affected by the distribution of species across the landscape. However, when analyzed separately, single-species flock occurrence showed a nested pattern, but mixed-species flock occurrence followed a random pattern. Fragment size and total bird density (as an indicator of the availability of individuals to join flocks) accounted for nestedness. At the individual species level, conspecific and heterospecific densities were the foremost factors increasing flock occurrence probabilities, suggesting that species tended to aggregate when there was an increase in the local availability of individuals. Fragment size and habitat structure (coniferous cover and number of thick trees) also increased flock occurrence, likely because of higher resource availability, which allowed the colonization of more species and individuals. Greater isolation reduced flock occurrence, maybe as a result of lower availability of individuals in distant fragments. Overall, fragmentation conditions can disrupt flocking behaviour of small insectivorous species, which could decrease survival and increase predation risk during winter. Keywords: nestedness, flock occurrence, fragmentation, insectivorous birds, winter flocks.

Removal of divalent heavy metal mixtures from water by Saccharomyces Cerevisiae using crossflow microfiltration

The removal of heavy metal ions, Ni 2+, Cu 2+ and Pb 2+ using yeast ( Saccharomyces cerevisiae) as carriers in a crossflow microfiltration is investigated. The effects of yeast cell and electrolyte concentrations on the transient and steady-state permeate flux and metal ion rejections are established. It is found that the metal ion rejection reaches a plateau if yeast cell concentration is greater than ∼2 g/l as a result of cell aggregation. The binding affinity of the metals to yeast cell is Pb 2+>Cu 2+>Ni 2+, which is also reflected in the metal ion rejection under identical process conditions. Because of the formation of yeast cell flocks in the presence of Pb 2+, permeate flux is also higher for this metal. The presence of NaCl decreases both rejection and permeate flux for Ni 2+ and Cu 2+ but not for Pb 2+. When binary or ternary metal mixtures are used, the rejection of the individual metals is reduced except that of Pb 2+. It is found that the pseudo-gel concentration is unaffected by the presence of metal ions.

Functionalization of latex particle surface by using polymeric inisurfs

In this work the emulsion polymerisation of styrene was carried out in presence of the inisurfs (reactive surfactants). The reaction kinetics was followed by dilatometric and calorimetric measurements. The influence of the inisurf concentration in reaction mixture as well as the reaction temperature on the particle properties were studied. Resulting particles were characterised with FFFF-MALLS and PCS. Viscosity measurements indicate the formation of particle flocks in the solution at certain inisurf concentration in reaction mixture.

Social environment and immunity in male red jungle fowl

We examined the relationship between social dominance, immune response, and ornamentation in captive red jungle fowl by comparing these variables in males housed individually with a single female to those in the same males after they were placed in flocks with an unfamiliar male and three unfamiliar females. Males with larger combs before being placed in the flocks were more likely to become dominant, and dominant males’ combs grew after flock formation, whereas subordinate males’ combs shrank. Immune response as reflected in hematocrit, immunoglobulin levels, and wing web swelling (a measure of cell-mediated immunity) was stronger in males that later became dominant, both before and after flock formation, although the difference between dominant and subordinate birds was more pronounced after males were housed in the multi-male groups. Dominant and subordinate males also differed in the relationship between comb length and wing web swelling. Among dominant males, individuals with larger combs had significantly larger swellings after flock formation, whereas within the subordinate males, those with relatively larger combs had worse cell-mediated immunity than those with smaller combs. These results suggest that males of different quality pay different costs to maintain both ornamentation and immune defense.

The evolution of communal roosting in birds: origin and secondary losses

Three main benefits are thought to underlie communal roosting in birds: a reduction in thermoregulation demands, a decrease in predation risk, and an increase in foraging efficiency. I investigated interspecific variation in communal roosting tendencies across categories of several ecological factors to examine the relevance of each functional hypothesis in the evolutionary transition to communal roosting and the secondary reversal to solitary roosting habits. The study phylogenetic tree included 30 families and 437 species. Evolutionary transitions to communal roosting occurred more often on branches with flocking species and with larger species but were not associated with diet, territoriality, geographical area, or time of day. The association with flocking activities suggests that increased foraging efficiency, a factor thought to operate through the formation of flocks, may have been a key factor in the origin of avian communal roosting. However, several transitions to communal roosting occurred on branches with nonflocking species, indicating that foraging efficiency may not be the only factor involved in the evolution of communal roosting. Secondary losses of communal roosting habits occurred on several branches, with a concomitant loss of flocking behavior and a tendency to exhibit territorial behavior and nocturnal foraging. Secondary losses suggest that communal roosting is costly to perform and maintain and may be lost when an asocial selection regime operates. The large number of exceptions to the above patterns may force a reevaluation of current functional hypotheses about communal roosting in birds.

Interactions among quantitative traits in the course of sympatric speciation.

Sympatric speciation, the origin of two or more species from a single local population, has almost certainly been involved in formation of several species flocks, and may be fairly common in nature. The most straightforward scenario for sympatric speciation requires disruptive selection favouring two substantially different phenotypes, and consists of the evolution of reproductive isolation between them followed by the elimination of all intermediate phenotypes. Here we use the hypergeometric phenotypic model to show that sympatric speciation is possible even when fitness and mate choice depend on different quantitative traits, so that speciation must involve formation of covariance between these traits. The increase in the number of variable loci affecting fitness facilitates sympatric speciation, whereas the increase in the number of variable loci affecting mate choice has the opposite effect. These predictions may enable more cases of sympatric speciation to be identified.

Initial winter flock formation in the Willow Tit Parus montanus. Do immigrating juveniles assess the quality of territorial adults?

In the Willow Tit Parus montanus, forming of winter flocks starts shortly after the juveniles have become independent of their parents. In the early phase of flock formation the juveniles roam about prospecting for suitable winter territories. They visit several occupied territories in succession and seek contact with the territory holders. I describe the behaviour of juveniles during such encounters with adult conspecifics. I suggest that, by approaching adults closely and behaving specifically, juveniles gain important information on the adults' innate qualities; this may affect the settling juveniles' future survival.

Marbled Murrelets as Initiators of Feeding Flocks in Prince William Sound, Alaska

-I sought to determine which seabird species initiated small, ephemeral, multispecies feeding flocks in Prince William Sound, AK (PWS). I observed 47 feeding flocks at five sites duringJune 1996 and determined the initiating species at 34. All of the latter flocks were initiated by pursuit divers, of which 76.5% were Marbled Murrelets (Brachyramphus marmoratus), the most abundant seabird in PWS. Formation of feeding flocks followed either of two scenarios: 1) larids were attracted to a feeding location by the presence or activity of Marbled Murrelets (26.9%), or 2) both larids and murrelets were present and flock feeding began after the murrelets dove from the surface (50.0%). Other principal participants were Black-legged Kittiwakes (Rissa tridactyla) and Glaucous-winged Gulls (Larus glaucescens). Received 14 April 1999, accepted I June 1999.

Seasonal, Diel, and Spatial Dispersion Patterns of Golden Eagle Autumn Migration in Southwestern Montana

In this report we describe three behavioral phenomena of Golden Eagle (Aquila chrysaetos) fall migration: agespecific seasonal differential migration, age-specific diel patterns of migration, and the spatial dispersion pattern of migrating Golden Eagles. Immature individuals of many North American raptor species migrate earlier in the season than adults (see Appendix 2 in Kerlinger 1989). As resource levels decline in the fall, less efficient foragers (Hoffman 1985) or subordinate birds (Gauthreaux 1978) are likely to be the first to seek resources elsewhere. Hoffman and Potts (1985) reported that immature Golden Eagles migrate earlier in the season than adults although Kerlinger (1989) reported the reverse. We examined our data to address whether there was seasonal differential migration between age classes of Golden Eagles migrating along the Bridger Range. Because different travel requirements or behavioral differences between age classes may result in age-specific migration patterns within periods of the day, we also investigated whether immature and adult eagles had different diel patterns of migration. A migrating raptor searching for lift may locate an updraft by flying towards other soaring birds. Such visual interaction among migrants would result in aggregation. This is similar to Kerlinger's (1985) aggregation model for flock formation. While his model applies to species that typically migrate in flocks, other species that do not form discrete flocks may still exhibit nonrandom dispersion due to visual interaction. Alternatively, Golden Eagles may avoid other eagles during migration. Pairs of Golden Eagles space out the nests that they use in a given year more regularly than random (Watson and Rothery 1986) and their territorial behavior may carry over to the migration season. In that case we would observe even dispersion. For aggregation or repulsion due to visual interaction to occur, concentrations of migrants would have to be sufficiently dense that individuals could see each other. Furthermore, aggregations of aerodynamically dissimilar birds would be ephemeral because of different climb and glide characteristics so it is appropriate to focus on concentrations of aerodynamically similar birds, e.g., birds of the same species, when testing for nonrandom dispersion. Golden Eagles passed our lookouts in sufficient densities that if they respond to the presence of other soaring Golden Eagles we should have observed nonrandom dispersion.

Brood amalgamation in the Bristle‐thighed Curlew Numenius tahitiensis: process and function

Alloparental care in birds generally involves nonbreeding adults that help at nests or breeding adults that help raise young in communal nests. A less often reported form involves the amalgamation of broods, where one or more adults care for young that are not their own. We observed this phenomenon among Bristle‐thighed Curlew Numenius tahitiensis broods in western Alaska during 1990–1992. Amalgamation of broods generally involved the formation of temporary and extended associations. Temporary associations were formed by the incidental convergence of broods soon after they left their nests. During this period, parents defended distinct brood‐rearing areas, were antagonistic to conspecifics and remained together for less than 3 days. Extended associations formed when chicks were 1–2 weeks old. Here, parents and their broods occupied distinct, but adjacent, brood‐rearing areas and moved around as a unit. Whether a brood participated in either temporary or extended associations or remained solitary appeared to depend on brood density in the immediate area and on hatching date. When chicks were 3–4 weeks old, aggregations of up to ten broods formed wherein young mixed and parents defended a common brood‐rearing area. All broods (n = 48) that survived to fledging joined such aggregations. Alloparental care involved only antipredator defence and was not associated with activities such as feeding and brooding. Most female parents abandoned their broods shortly after the young could fly and when aggregations were forming. The female parent of a pair always deserted its young before or on the same day as the male parent and, in every aggregation, one or two males continued to tend young for about 5 days longer than other male parents. In most cases, adults deserted the young 2–6 days before the young departed the area when about 38 days old. Bristle‐thighed Curlews also formed temporary associations with American and Pacific Golden Plover Pluvialis dominica and Pluvialis fulva, Whimbrel Numenius phaeopus, Bar‐tailed Godwit Limosa lapponica, Western Sandpiper Cal‐idris mauri and Long‐tailed Skua Stercorarius longicaudus. Curlews and other larger bodied species commonly attack‐mobbed predators together, whereas smaller bodied species generally gave alarm calls and circled the predators. For all species, the intensity of antipredator defence by attending adults gradually decreased as young became older and aggregations formed. We suggest that amalgamation of broods among Bristle‐thighed Curlew enhances predator defence, aids in the process of flock formation for migrating young, and allows females and some males to desert their young earlier.

Surface area enhancement of silica fibers by sol-gel processes

Non-porous silica fibers, 1 μm in diameter and up to 100 μm long, have been coated by dispersion in silica sols in order to increase their specific surface area and improve the adsorption capacity for chromatographic bioseparations. Both acid- and base-catalyzed sols were investigated. Coatings with an acid-catalyzed sol resulted in a hundredfold increase in the specific surface area of the fiber. However, formation of fiber flocks by this method caused problems in packing chromatographic columns with these fibers. By contrast, coatings by dispersion in base-catalyzed sols resulted in looser flocks that facilitated column packing. Various sol compositions and fiber mass concentrations in base-catalyzed sols increased the specific surface area of the fibers by up to 30 times. Washing with acetone or ethanol reduced the specific surface area of the coated fibers by about 80%.

Production and separation of algae in a high-rate ponds system

Pilot scale high-rate algal ponds followed by settling tanks were developed to produce algal biomass from wastewater for greenery development and agricultural use in arid zones, like Kuwait. The high-rate ponds designed and operated by instructions resulting from the authors' research work can produce algal biomass of 300–400 kg/ha. d in summer and 200–300 kg/ha.d in winter seasons. The actual yield depends on the efficiency of the floc formation and settling. A minimum of a 2-h residence time in the settling tanks is needed to achieve adequate separation of the phases, assuming healthy algae culture that are susceptible to flock formation. The flock formation and settling properties are sensitive to the weather and operational parameters (e.g., sunshine, hydraulic conditions in settling tank, variations of the flow rate, and pond depth). If conditions are inadequate, 20–30% of the biomass can be lost. Satisfactory biomass production can be achieved only with careful plant operation and maintenance. The sensitivity of the algae separation by settling operation indicated the development of a modified sand filter system for algae trapping.

Larids, Scolopacids, and Passerines Exploiting Ephemeral Prey at Talan Island, Russia

We report an unusual multispecies foraging assemblage that included larids, shorebirds and passerines which exploited a highly concentrated and ephemeral prey source over a period of three days in July and August 1988. During studies of breeding biology, food-habits and host-parasite ecology among a diverse colonial avifauna at Talan Island in the northern Sea of Okhotsk (59018'N; 149002'E) we observed the formation of mixed-species flocks during extreme high tides of 31 July, 1 August, and 13 August 1988. The first assemblage involved a maximum of 60 birds, including about 45 black-legged kittiwakes (Rissa tridactyla) and 15 slaty-backed gulls (Larus schistisaugus). Feeding activity was intense within 1-3 m of the shore. All birds swam slowly while vigorously dipping and picking minuscule prey items from the surface of the water. The duration of foraging by this flock was not determined. As birds dispersed, we were able to collect numerous pupae and late instar larvae (3-7.3 mm in length) of small dipterans that were washed from the shoreline during the high tide. Detailed observations were made on flocks that assembled in early August. In the first flock, feeding activity extended over 140 min in the late morning to early afternoon of 1 August. This flock was initially composed of adult R. tridactyla feeding along 30 m of cobble beach at a distance of <1 m from shore. As before, there was a gentle surge that washed pupae and larvae from the cobble beach. Whitish larvae and black pupae were visible up to 10-15 m from shore. Within 30 min of initial feeding activity there were 19 adult R. tridactyla, and 12 adult and 3 first year L. schistisaugus. At 75 min there were 52 R. tridactyla and 21 L. schistisaugus vigorously picking larvae and pupae from surface film. Other species of marine birds were not observed. Agonistic interactions between kittiwakes and gulls were not observed. During the peak of foraging activity, feeding intensity by individual birds ranged from 17-31 dips per 30 sec interval (N = 5; 5 = 25). At about 135 min the flock began to disperse, and gulls departed prior to the kittiwakes. The final assemblage lasted for 90 min and was similar to those previously described, being composed of 71 adult R. tridactyla, and 12 adult and a young of the year L. schistisaugus. However, we also observed 3 ruddy turnstones (Arenaria interpres), 10 wood sandpipers (Tringa glareola), 4 common sandpipers (Actitis hypoleucos) and several white wagtails (Motacilla alba) simultaneously feeding among the cobbles in the splash zone adjacent to the larids. All species were feeding on dipteran larvae and pupae. Although all birds were in close proximity, we observed no agonistic interactions.

Flocking and feeding in the white‐fronted chat Ephthianura albifrons: The relationship between diet, food availability and patch selection

AbstractCensuses of white‐fronted chats were conducted three times per day, four times per month for more than 2 years in a salt‐marsh/grassland near Melbourne. Most birds Were in flocks of less than 10, although flocks of up to 50 were recorded. Diet was determined by stomach flushing 226 birds over a 12 month period and the abundance of their arthropod prey was sampled in pitfall and sticky traps located in areas where flocks aggregated and in areas where few birds were found. Diptera and Coleoptera were the major components of the diet, although the actual species varied throughout the year. On 8 of 9 occasions when differences in prey density were detected, birds aggregated in the more profitable patches. These observations suggest a relationship between food‐finding and flock formation but cannot eliminate the possibility of flocking functioning as an anti‐predator strategy.