scholarly journals Distribution and density of oxpeckers on giraffes in Hwange National Park, Zimbabwe

2019 ◽  
Author(s):  
Roxanne Gagnon ◽  
Cheryl T. Mabika ◽  
Christophe Bonenfant

AbstractOxpeckers (Buphagus sp.) are two bird species closely associated to large mammals, including giraffes (Giraffa camelopardalis). We tested whether oxpeckers distributed themselves at random across individuals or aggregated on individual giraffes, and if birds select the host’s body parts with the expected greatest amount of ticks. By counting oxpeckers on giraffe’s body from photographs, we quantified the distribution of birds per hosts and over predefined zones on the giraffe body. Oxpeckers displayed a strong aggregation behaviour with few hosts carrying many birds while many carried a limited number or no birds, a pattern that was most exaggerated for males. Oxpeckers were disproportionately found on the mane and back, where the density of ticks is presumably the highest. This high aggregation level of birds is typical of parasitic species and could suggest that oxpecker distribution may mirror the distribution of ticks, their primary food resource, on giraffes. Abundance of ticks appears as a major driver of the oxpecker foraging behaviour, and the oxpecker–large herbivores system proves to be highly relevant for the study of host–parasite dynamics.


1997 ◽  
Vol 24 (1) ◽  
pp. 27 ◽  
Author(s):  
Harry F. Recher ◽  
William E. Davis Jr

Mulga is a distinctive woodland or shrub community with a wide distribution across the semi-arid zone of southern and central Australia. Mulga (Acacia aneura) is the dominant shrub and small tree, but other species of Acacia are common. Typical of Australian habitats in the arid zone, mulga has a core of resident bird species that is augmented by nomadic (opportunistic) species when conditions are favourable. This paper describes the foraging behaviour and habitat use of a mulga avifauna in the vicinity of Alice Springs during late winter, when many opportunistic species were present. Data were obtained for 24 species, of which 16 were confirmed as nesting. Many birds, regardless of their normal foraging habits, converged on a common food resource: a geometrid moth (Geometridae) that was abundant on mulga plants. Despite their use of a common food resource, species differed in their foraging behaviour, proportions of different substrates used, and foraging heights. Ground-foraging species dominated the avifauna, but in most respects the guild structure of the community was a scaled-down version of Eucalyptus forest avifaunas. Differences in guild structure between mulga and eucalypt forest are best explained by differences between the two habitats in the kinds of resources (e.g. foraging substrates, types of food) that are available.



2021 ◽  
Author(s):  
Luz Garcia-Longoria ◽  
Jaime Muriel ◽  
Sergio Magallanes ◽  
Zaira Hellen Villa-Galarce ◽  
Leonila Ricopa ◽  
...  

Abstract Characterizing the diversity and structure of host-parasite communities is crucial to understanding their eco-evolutionary dynamics. Malaria and related haemosporidian parasites are responsible for fitness loss and mortality in bird species worldwide. However, despite exhibiting the greatest ornithological biodiversity, avian haemosporidians from Neotropical regions are quite unexplored. Here, we analyse the genetic diversity of bird haemosporidian parasites (Plasmodium and Haemoproteus) in 1,336 individuals belonging to 206 bird species to explore for differences in diversity of parasite lineages and bird species across five well-differentiated Peruvian ecoregions. We detected 70 different haemosporidian lineages infecting 74 bird species. We showed that 25 out of the 70 haplotypes had not been previously recorded. Moreover, we also identified 81 new host – parasite interactions representing new host records for these haemosporidian parasites. Our outcomes revealed that the effective diversity (as well as the richness, abundance, and Shannon-Weaver index) for both birds and parasite lineages was higher in Amazon basin ecoregions. Furthermore, we also showed that ecoregions with greater diversity of bird species also had high parasite richness, hence suggesting that host community is crucial in explaining parasite richness. Generalist parasites were found in ecoregions with lower bird diversity, implying that the abundance and richness of hosts may shape the exploitation strategy followed by haemosporidian parasites. These outcomes reveal that Neotropical region is a major reservoir of unidentified haemosporidian lineages. Further studies analysing host distribution and specificity of these parasites in the tropics will provide important knowledge about phylogenetic relationships, phylogeography, and patterns of evolution and distribution of haemosporidian parasites.



Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 94
Author(s):  
Alain Hambuckers ◽  
Simon de Harenne ◽  
Eberth Rocha Ledezma ◽  
Lilian Zúñiga Zeballos ◽  
Louis François

Species distribution models (SDMs) are commonly used with climate only to predict animal distribution changes. This approach however neglects the evolution of other components of the niche, like food resource availability. SDMs are also commonly used with plants. This also suffers limitations, notably an inability to capture the fertilizing effect of the rising CO2 concentration strengthening resilience to water stress. Alternatively, process-based dynamic vegetation models (DVMs) respond to CO2 concentration. To test the impact of the plant modelling method to model plant resources of animals, we studied the distribution of a Bolivian macaw, assuming that, under future climate, DVMs produce more conservative results than SDMs. We modelled the bird with an SDM driven by climate. For the plant, we used SDMs or a DVM. Under future climates, the macaw SDM showed increased probabilities of presence over the area of distribution and connected range extensions. For plants, SDMs did not forecast overall response. By contrast, the DVM produced increases of productivity, occupancy and diversity, also towards higher altitudes. The results offered positive perspectives for the macaw, more optimistic with the DVM than with the SDMs, than initially assumed. Nevertheless, major common threats remain, challenging the short-term survival of the macaw.



Author(s):  
Verena Rösch ◽  
Pascal Aloisio ◽  
Martin H. Entling

AbstractVineyards can be valuable habitats for biodiversity conservation. For example, in Rhineland-Palatinate (Germany) over a third of the state’s critically endangered Woodlark (Lullula arborea) population breeds in vineyards along the western margin of the Upper Rhine Valley. We here aim to elucidate how local ground cover management, food availability and the proximity to settlements affect territory selection by this bird species in the region. As climate, site conditions and management differ greatly from more continental or Mediterranean wine-growing areas, conditions for Woodlark conservation may differ as well.We compared 26 Woodlark territories in vineyards with 26 nearby reference areas from which Woodlarks were absent. We recorded vineyard ground cover in the inter-rows (% cover) as well as vegetation height and composition (forbs vs. grasses). Arthropods were sampled using pitfall traps, since they are the main food resource of Woodlarks during the breeding season. In addition, the distance to built-up areas was measured. The vegetation in Woodlark territories was shorter (mean 14.2 vs. 19.6 cm) and more dominated by forbs (39% vs. 27% cover) than in absence areas. The vegetation cover in the inter-rows had no effect on Woodlark territory presence or absence. Woodlarks also favoured areas with a higher abundance of arthropods (mean abundance 69.1 vs. 57.5) and a greater distance to built-up areas (mean distance 554 vs. 373 m). We conclude that to promote the Woodlark in wine-growing areas, short, forb-rich swards should be created, facilitating arthropod detectability. This is likely to require low levels of nitrogen fertilization since fertilizers favour tall-growing grasses that outcompete forbs. Pesticide applications should be kept at a minimum to enhance arthropods as the main food source for Woodlarks and their chicks. In addition, the expansion of settlements into breeding areas of Woodlarks should be avoided.



2001 ◽  
Vol 212 (3) ◽  
pp. 345-354 ◽  
Author(s):  
THOMAS FLATT ◽  
NICOLAS MAIRE ◽  
MICHAEL DOEBELI


1997 ◽  
Vol 59 (3) ◽  
pp. 427-450 ◽  
Author(s):  
Veijo Kaitala ◽  
Mikko Heino ◽  
Wayne M. Getz


2010 ◽  
Vol 10 (4) ◽  
pp. 195-203 ◽  
Author(s):  
Ivan Sazima ◽  
Cristina Sazima

Several bird species feed on a variety of external parasites and epibionts, organic debris, dead and wounded tissue, clots and blood, and secretions from the body of other vertebrates (hosts or clients). We present an overview of so called cleaner birds from the Neotropics based on field records, literature, and photo survey. We found that 33 bird species in 16 families practice cleaning even if some of them do so very occasionally. The birds range from the Galápagos ground finch Geospiza fuliginosa to the widespread black vulture Coragyps atratus. Clients mostly are large herbivores such as capybaras, deer, and livestock, but also include medium-sized herbivores such as iguanas and tortoises, and carnivores such as boobies and seals - a few bird species associate with these latter marine mammals. No carnivorous terrestrial mammal client is recorded to date except for a domestic dog, from whose hair black vultures picked organic debris. Some clients adopt particular inviting postures while being cleaned, whereas others are indifferent or even disturbed by the activity of cleaner birds. Capybaras, giant tortoises, and iguanas are among the inviting clients, whereas boobies try to dislodge the 'vampire' finch Geospiza difficilis. Most of the Neotropical cleaner birds may be lumped in one broad category (omnivores that dwell in open areas and associate with large to medium-sized herbivores). A second, restricted category accommodates some species from Patagonia and the Galápagos Islands (omnivores that dwell in open areas and associate with carnivorous marine mammals, or seabirds and marine reptiles). Two still more restricted categories accommodate the following: 1) forest-dwelling cleaner birds; and 2) marine coastal cleaners. Additional records of Neotropical cleaner birds will mostly fall in the broad category.



2002 ◽  
Vol 62 (2) ◽  
pp. 339-346 ◽  
Author(s):  
J. RAGUSA-NETTO

Figs are a remarkable food resource to frugivores, mainly in periods of general fruit scarcity. Ficus calyptroceras Miq. (Moraceae) is the only fig species in a type of dry forest in western Brazil. In this study I examined the fruiting pattern as well as fig consumption by birds in F. calyptroceras. Although rainfall was highly seasonal, fruiting was aseasonal, since the monthly proportion of fruiting trees ranged from 4% to 14% (N = 50 trees). I recorded 22 bird species feeding on figs. In the wet season 20 bird species ate figs, while in the dry season 13 did. Parrots were the most important consumers. This group removed 72% and 40% of the figs consumed in the wet and dry seasons, respectively. No bird species increases fig consumption from dry to wet season. However, a group of bird species assumed as seed dispersers largely increases fig consumption from wet to dry season, suggesting the importance of this resource in the period of fruit scarcity. The results of this study points out the remarkable role that F. calyptroceras plays to frugivorous birds, in such a dry forest, since its fruits were widely consumed and were available all year round.



2021 ◽  
Author(s):  
Hannelore MacDonald ◽  
Dustin Brisson

Parasite-host interactions can result in periodic population dynamics when parasites over-exploit host populations. The timing of host seasonal activity, or host phenology, determines the frequency and demographic impact of parasite-host interactions which may govern if the parasite can sufficiently over-exploit their hosts to drive population cycles. We describe a mathematical model of a monocyclic, obligate-killer parasite system with seasonal host activity to investigate the consequences of host phenology on host-parasite dynamics. The results suggest that parasites can reach the densities necessary to destabilize host dynamics and drive cycling in only some phenological scenarios, such as environments with short seasons and synchronous host emergence. Further, only parasite lineages that are sufficiently adapted to phenological scenarios with short seasons and synchronous host emergence can achieve the densities necessary to over-exploit hosts and produce population cycles. Host-parasite cycles can also generate an eco-evolutionary feedback that slows parasite adaptation to the phenological environment as rare advantageous phenotypes are driven to extinction when introduced in phases of the cycle where host populations are small and parasite populations are large. The results demonstrate that seasonal environments can drive population cycling in a restricted set of phenological patterns and provides further evidence that the rate of adaptive evolution depends on underlying ecological dynamics.



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