Academic literature on the topic 'Zosterops lateralis'

The ability of migratory silvereyes to orient was tested in the geomagnetic field with one eye covered. Silvereyes using only their right eye were able to orient in migratory direction just as well as birds using both eyes. Using only their left eye, however, the birds did not show a significant directional preference. These data indicate that directional information from the magnetic field is mediated almost exclusively by the right eye and processed by the left hemisphere of the brain. Together with corresponding findings from European robins and indications for a similar phenomenon in homing pigeons, they suggest that a strong lateralisation of the magnetic compass is widespread among birds.

The main objective of my investigation was to ascertain the prevalence and impact of avian pox in New Zealand silvereyes (Zosterops lateralis). Silvereyes were mist--‐netted between 2010 and 2012 in three locations of the South Island and were examined for external signs of avian pox. Of the 409 silvereyes captured over this time period, avian pox lesions were identified in 9 birds (2.2%) and were found in both sexes as well as in juveniles. The highest incidence of avian pox was seen on the west coast at Moana (7.2%) between late May and mid--‐June 2011. Overall prevalence for each location over the period of the survey ranged from 1% in Kaikoura, Christchurch 3.6% and Moana 3.5% suggesting only slight differences between populations. I next investigated the prevalence of avian pox in a community of forest passerines at Kowhai Bush Kaikoura in the spring of 2012. Pox lesions were observed in 2/492 of the birds caught. Both cases (3.8%, n=52) were in the introduced chaffinch (Fringilla coelebs). Pox occurred in < 1% of individuals of the introduced species (n=313) and was absent in all native and endemic species (n=189). No pox lesions were seen in silvereyes captured in the 2012 Kaikoura survey (0/69). White blood cell profiles, fat scores and mass where also compared between silvereyes with and without avian pox lesions but no differences were found, however, the small sample of individuals with pox meant the power to detect a difference was low. A review of the literature on avian pox revealed a similar low prevalence of avian pox to that seen in this study and the prevalence of avian pox seen in other populations of white--‐eyes in New Zealand and elsewhere. However, across a range of other passerine species, avian pox was significantly more prevalent in geographically isolated endemic species than other groups. My investigation suggests that avian pox needs to be monitored over extended periods to estimate its prevalence and how its epizootiology is influenced by a variety of biotic and abiotic factors. Furthermore, my investigation reveals the need for more information, including the identification of the type and virulence of strains present in New Zealand and the role that silvereyes and introduced birds may have on the dynamics of avian pox in rare endemic birds. The main objective of my investigation was to ascertain the prevalence and impact of avian pox in New Zealand silvereyes (Zosterops lateralis). Silvereyes were mist--‐netted between 2010 and 2012 in three locations of the South Island and were examined for external signs of avian pox. Of the 409 silvereyes captured over this time period, avian pox lesions were identified in 9 birds (2.2%) and were found in both sexes as well as in juveniles. The highest incidence of avian pox was seen on the west coast at Moana (7.2%) between late May and mid--‐June 2011. Overall prevalence for each location over the period of the survey ranged from 1% in Kaikoura, Christchurch 3.6% and Moana 3.5% suggesting only slight differences between populations. I next investigated the prevalence of avian pox in a community of forest passerines at Kowhai Bush Kaikoura in the spring of 2012. Pox lesions were observed in 2/492 of the birds caught. Both cases (3.8%, n=52) were in the introduced chaffinch (Fringilla coelebs). Pox occurred in < 1% of individuals of the introduced species (n=313) and was absent in all native and endemic species (n=189). No pox lesions were seen in silvereyes captured in the 2012 Kaikoura survey (0/69). White blood cell profiles, fat scores and mass where also compared between silvereyes with and without avian pox lesions but no differences were found, however, the small sample of individuals with pox meant the power to detect a difference was low. A review of the literature on avian pox revealed a similar low prevalence of avian pox to that seen in this study and the prevalence of avian pox seen in other populations of white--‐eyes in New Zealand and elsewhere. However, across a range of other passerine species, avian pox was significantly more prevalent in geographically isolated endemic species than other groups. My investigation suggests that avian pox needs to be monitored over extended periods to estimate its prevalence and how its epizootiology is influenced by a variety of biotic and abiotic factors. Furthermore, my investigation reveals the need for more information, including the identification of the type and virulence of strains present in New Zealand and the role that silvereyes and introduced birds may have on the dynamics of avian pox in rare endemic birds.

Birds are a major pest in vineyards both in New Zealand and overseas. There is a need for new behavioural research on birds' foraging habits and feeding preferences in vineyards, as much of the literature to date is anecdotal. Research on cues to birds' feeding will provide a basis on which new deterrent and control strategies can be devised. Spatial-and temporal bird damage in a small vineyard block was mapped to find if damage was correlated with grape maturity and environmental factors. Vineyard and field observations of bird behaviour using video technology combined with preference experiments aimed to establish the relative roles of grape sugar concentration and colour in avian selection. Proximity of vineyards to bird roosts affects damage levels, regardless of differing maturity between locations. The rate of damage tends to increase exponentially once grape maturity has passed a threshold of 13 °Brix. Bunches positioned closest to the ground receive more damage if blackbirds or song thrushes are the predominant pests. Both sugar concentration and grape colour were found to affect birds' feeding preference, but the importance of the two factors varied between years. Black and green grape varieties were differentially preferred by blackbirds (Turdus merula) and song thrushes (Turdus philomelos) while silvereyes (Zosterops lateralis) appeared to have no strong colour preference. It was apparent that there were other, not assessed, grape factors that also affect selection. In small unprotected vineyards that are adjacent to bird roosts the entire grape crop can be taken by bird pests. Besides removing the roosts, which can be beneficial shelterbelts in regions exposed to high winds, growers currently may have no alternative other than to use exclusion netting to keep crops intact. The differential preferences between bird species for variety characteristics suggest that any new deterrents and other strategies to deflect birds from grape crops may need to be species-specific.

Impact assessments increasingly rely on models to project the potential impacts of climate change on species distributions. Ecological niche models have become established as an efficient and widely used method for interpolating (and sometimes extrapolating) species’ distributions. They use statistical and machine-learning approaches to relate species’ observations to environmental predictor variables and identify the main environmental determinants of species’ ranges. Based on this estimated species–environment relationship, the species’ potential distribution can be mapped in space (and time). In this chapter, we explain the concept and underlying assumptions of ecological niche models, describe the basic modelling steps using the silvereye (Zosterops lateralis) as a simple real-world example, identify potential sources of uncertainty in underlying data and in the model, and discuss potential limitations as well as latest developments and future perspectives of ecological niche models in a global change context.