MDR :: Browsing by Author "Gagliardo, Anna"

Browsing by Author "Gagliardo, Anna"

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Data from: Anosmia impairs homing orientation but not foraging behaviour in free-ranging shearwaters
(2017-09-02) Padget, Oliver; Dell'Ariccia, Gaia; Gagliardo, Anna; González-Solís, Jacob; Guilford, Tim
Shearwaters deprived of their olfactory sense before being displaced to distant sites have impaired homing ability but it is unknown what the role of olfaction is when birds navigate freely without their sense of smell. Furthermore, treatments used to induce anosmia and to disrupt magneto-reception in displacement experiments might influence non-specific factors not directly related to navigation and, as a consequence, the results of displacement experiments can have multiple interpretations. To address this, we GPS-tracked the free-ranging foraging trips of incubating Scopoli’s shearwaters within the Mediterranean Sea. As in previous experiments, shearwaters were either made anosmic with 4% zinc sulphate solution, magnetically impaired by attachment of a strong neodymium magnet or were controls. We found that birds from all three treatments embarked on foraging trips, had indistinguishable at-sea schedules of behaviour and returned to the colony having gained mass. However, we found that in the pelagic return stage of their foraging trips, anosmic birds were not oriented towards the colony but that coastal navigation was unaffected. These results support the case for zinc sulphate having a specific effect on the navigational ability of shearwaters and thus the view that seabirds consult an olfactory map to guide them across seascapes.
Data from: Deconstructing the flight paths of hippocampal-lesioned homing pigeons as they navigate near home offers insight into spatial perception and memory without a hippocampus
(2022-08-30) Gagliardo, Anna; Cioccarelli, Sara; Giunchi, Dimitri; Pollonara, Enrica; Colombo, Silvia; Casini, Giovanni; Bingman, Verner P.
The aim of this study was to exploit detailed analyses of GPS-recorded tracks to better characterise the impact of hippocampal (HF) lesion on spatial memory and perception in the context of homing pigeon navigation when reliant on familiar landscape features near the home loft following repeated releases from the same three locations. As reported previously, following HF lesion, a low spatio-temporal resolution analysis revealed that homing pigeons fly less direct paths home once near the loft. We now further show that 1) HF-lesioned pigeons are less likely to display fidelity to a particular flight path home when released from the same locations multiple times, 2) intact pigeons are more likely to exploit leading-line landscape features, e.g., a road or the border of a woodlot, in developing flight-path fidelity and 3) even when flying a straight path HF-lesioned homing pigeons are more likely to display relatively rapid, oscillatory heading changes as if casting about for sensory, presumably visual information. The flight behaviour differences between the intact and HF-lesioned pigeons persisted across the four releases from the three locations, although the differences became smaller with increasing experience. Taken together, the GPS-track data offer a detailed characterisation of the effects of HF lesion on landscape-based, homing pigeon navigation, offering new insight into the role of the hippocampal formation in supporting memory-related, e.g., fidelity to a familiar route home, and perhaps perceptual-related, e.g., oscillating headings, navigational processes.
Data from: Evidence for pre-mnemonic, perceptual neglect of environmental features in hippocampal lesioned pigeons during homing
(2014-07-31) Gagliardo, Anna; Pollonara, Enrica; Coppola, Vincent J; Santos, Carlos David; Bingman, Verner P.
The importance of the vertebrate hippocampus in spatial cognition is often related to its broad role in memory. However, in birds, the hippocampus appears to be more specifically involved in spatial processes. The maturing of GPS-tracking technology has enabled a revolution in navigation research, including the expanded possibility of studying brain mechanisms that guide navigation in the field. By GPS-tracking homing pigeons released from distant, unfamiliar sites prior to and after hippocampal lesion, we observed, as has been reported previously, impaired navigational performance postlesion over the familiar/memorized space near the home loft, where topographic features constitute an important source of navigational information. The GPS-tracking revealed that many of the lost pigeons, when lesioned, approached the home area, but nevertheless failed to locate their loft. Unexpectedly, when they were hippocampal-lesioned, the pigeons showed a notable change in their behaviour when navigating over the unfamiliar space distant from home; they actually flew straighter homeward-directed paths than they did prelesion. The data are consistent with the hypothesis that, following hippocampal lesion, homing pigeons respond less to unfamiliar visual, topographic features encountered during homing, and, as such, offer the first evidence for an unforeseen, perceptual neglect of environmental features following hippocampal damage.
Data from: GPS-profiling of retrograde navigational impairments associated with hippocampal lesion in homing pigeons
(2021-06-15) Gagliardo, Anna; Colombo, Silvia; Pollonara, Enrica; Casini, Giovanni; Rossino, Maria Grazia; Wikelski, Martin; Bingman, Verner P.
The avian hippocampal formation (HF) is homologous to the mammalian hippocampus and plays a central role in the control of spatial cognition. In homing pigeons, HF supports navigation by familiar landmarks and landscape features. However, what has remained relatively unexplored is the importance of HF for the retention of previously acquired spatial information. For example, to date, no systematic GPS-tracking studies on the retention of HF-dependent navigational memory in homing pigeons have been performed. Therefore, the current study was designed to compare the pre- and post-surgical navigational performance of sham-lesioned control and HF-lesioned pigeons tracked from three different sites located in different directions with respect to home. The pre- and post-surgical comparison of the pigeons’ flight paths near the release sites and before reaching the area surrounding the home loft (4 km radius from the loft) revealed that the control and HF-lesioned pigeons displayed similarly successful retention. By contrast, the HF-lesioned pigeons displayed dramatically and consistently impaired retention in navigating to their home loft during the terminal phase of the homing flight near home, i.e., where navigation is supported by memory for landmark and landscape features. The data demonstrate that HF lesions lead to a dramatic loss of pre-surgically acquired landmark and landscape navigational information while sparing those mechanisms associated with navigation from locations distant from home.
Data from: Homing pigeons only navigate in air with intact environmental odours: a test of the olfactory activation hypothesis with GPS data loggers [full dataset]
(2012-04-01) Gagliardo, Anna; Ioalè, Paolo; Filannino, Caterina; Wikelski, Martin
A large body of evidence has shown that anosmic pigeons are impaired in their navigation. However, the role of odours in navigation is still subject to debate. While according to the olfactory navigation hypothesis homing pigeons possess a navigational map based on the distribution of environmental odours, the olfactory activation hypothesis proposes that odour perception is only needed to activate a navigational mechanism based on cues of another nature. Here we tested experimentally whether the perception of artificial odours is sufficient to allow pigeons to navigate, as expected from the olfactory activation hypothesis. We transported three groups of pigeons in air-tight containers to release sites 53 and 61 km from home in three different olfactory conditions. The Control group received natural environmental air; both the Pure Air and the Artificial Odour groups received pure air filtered through an active charcoal filter. Only the Artificial Odour group received additional puffs of artificial odours until release. We then released pigeons while recording their tracks with 1 Hz GPS data loggers. We also followed non-homing pigeons using an aerial data readout to a Cessna plane, allowing, for the first time, the tracking of non-homing homing pigeons. Within the first hour after release, the pigeons in both the Artificial Odour and the Pure Air group (receiving no environmental odours) showed impaired navigational performances at each release site. Our data provide evidence against an activation role of odours in navigation, and document that pigeons only navigate well when they perceive environmental odours.
Data from: Homing pigeons only navigate in air with intact environmental odours: a test of the olfactory activation hypothesis with GPS data loggers [partial dataset]
(2012-03-29) Gagliardo, Anna; Ioalè, Paolo; Filannino, Caterina; Wikelski, Martin
NOTE: A corrected version of this dataset is available. See doi:10.5441/001/1.2sr7mm39. ABSTRACT: A large body of evidence has shown that anosmic pigeons are impaired in their navigation. However, the role of odours in navigation is still subject to debate. While according to the olfactory navigation hypothesis homing pigeons possess a navigational map based on the distribution of environmental odours, the olfactory activation hypothesis proposes that odour perception is only needed to activate a navigational mechanism based on cues of another nature. Here we tested experimentally whether the perception of artificial odours is sufficient to allow pigeons to navigate, as expected from the olfactory activation hypothesis. We transported three groups of pigeons in air-tight containers to release sites 53 and 61 km from home in three different olfactory conditions. The Control group received natural environmental air; both the Pure Air and the Artificial Odour groups received pure air filtered through an active charcoal filter. Only the Artificial Odour group received additional puffs of artificial odours until release. We then released pigeons while recording their tracks with 1 Hz GPS data loggers. We also followed non-homing pigeons using an aerial data readout to a Cessna plane, allowing, for the first time, the tracking of non-homing homing pigeons. Within the first hour after release, the pigeons in both the Artificial Odour and the Pure Air group (receiving no environmental odours) showed impaired navigational performances at each release site. Our data provide evidence against an activation role of odours in navigation, and document that pigeons only navigate well when they perceive environmental odours.
Data from: Identifying volatile organic compounds used for olfactory navigation by homing pigeons
(2020-10-12) Zannoni, Nora; Wikelski, Martin; Gagliardo, Anna; Raza, Atif; Kramer, Stefan; Seghetti, Chiara; Wang, Nijing; Edtbauer, Achim; Williams, Jonathan
Many bird species have the ability to navigate home after being brought to a remote, even unfamiliar location. Environmental odours have been demonstrated to be critical to homeward navigation in over 40 years of experiments, yet the chemical identity of the odours has remained unknown. In this study, we investigate potential chemical navigational cues by measuring volatile organic compounds (VOCs): at the birds’ home-loft; in selected regional forest environments; and from an aircraft at 180 m. The measurements showed clear regional, horizontal and vertical spatial gradients that can form the basis of an olfactory map for marine emissions (dimethyl sulphide, DMS), biogenic compounds (terpenoids) and anthropogenic mixed air (aromatic compounds), and temporal changes consistent with a sea-breeze system. Air masses trajectories are used to examine GPS tracks from released birds, suggesting that local DMS concentrations alter their flight directions in predictable ways. This dataset reveals multiple regional-scale real-world chemical gradients that can form the basis of an olfactory map suitable for homing pigeons.
Data from: Importance of the hippocampus for the learning of route fidelity in homing pigeons
(2020-09-29) Wikelski, Martin; Gagliardo, Anna; Bingman, Verner P.
The avian hippocampal formation (HF) is thought to regulate map-like memory representations of visual landmarks/landscape features and has more recently been suggested to be similarly important for the perceptual integration of landmarks/landscapes. Aspects of spatial memory and perception likely combine to support the now well-documented ability of homing pigeons to learn to retrace the same route when homing from familiar locations, leading to the prediction that damage to the HF would result in a diminished ability to repeatedly fly a similar route home. HF-lesioned homing pigeons were repeatedly released from three sites to assess the importance of the hippocampus as pigeons gradually learn a familiar route home guided by familiar landmark and landscape features. As expected, control pigeons displayed increasing fidelity to a familiar route home, and by inference, successful perceptual and memory processing of familiar landmarks/landscape features. By contrast, the impoverished route fidelity of the HF-lesioned pigeons indicated an impaired sensitivity to the same landmark/landscape features.
Data from: Oceanic navigation in Cory’s shearwaters—evidence for a crucial role of olfactory cues for homing after displacement
(2013-07-16) Gagliardo, Anna; Bried, Joël; Lambardi, Paolo; Luschi, Paolo; Wikelski, Martin; Bonadonna, Francesco
Pelagic birds, which wander in the open sea most of the year and often nest on small remote oceanic islands, are able to pinpoint their breeding colony even within an apparently featureless environment, such as the open ocean. The mechanisms underlying their surprising navigational performance are still unknown. In order to investigate the nature of the cues exploited for oceanic navigation, Cory's shearwaters, Calonectris borealis, nesting in the Azores were displaced and released in open ocean at about 800 km from their colony, after being subjected to sensory manipulation. While magnetically disturbed shearwaters showed unaltered navigational performance and behaved similarly to unmanipulated control birds, the shearwaters deprived of their sense of smell were dramatically impaired in orientation and homing. Our data show that seabirds use olfactory cues not only to find their food but also to navigate over vast distances in the ocean.
Data from: Olfaction and topography, but not magnetic cues, control navigation in a pelagic seabird: displacements with shearwaters in the Mediterranean Sea
(2015-10-27) Pollonara, Enrica; Luschi, Paolo; Guilford, Tim; Wikelski, Martin; Bonadonna, Francesco; Gagliardo, Anna
Pelagic seabirds wander the open oceans then return accurately to their habitual nest-sites. We investigated the effects of sensory manipulation on oceanic navigation in Scopoli’s shearwaters (Calonectris diomedea) breeding at Pianosa island (Italy), by displacing them 400 km from their colony and tracking them. A recent experiment on Atlantic shearwaters (Cory’s shearwater, Calonectris borealis) breeding in the Azores indicated a crucial role of olfaction over the open ocean, but left open the question of whether birds might navigate by topographical landmark cues when available. Our experiment was conducted in the Mediterranean sea, where the availability of topographical cues may provide an alternative navigational mechanism for homing. Magnetically disturbed shearwaters and control birds oriented homeward even when the coast was not visible and rapidly homed. Anosmic shearwaters oriented in a direction significantly different from the home direction when in open sea. After having approached a coastline their flight path changed from convoluted to homeward oriented, so that most of them eventually reached home. Beside confirming that magnetic cues appear unimportant for oceanic navigation by seabirds, our results support the crucial role of olfactory cues for birds’ navigation and reveal that anosmic shearwaters are able to home eventually by following coastal features.
Data from: Only natural local odours allow homeward orientation in homing pigeons released at unfamiliar sites
(2018-08-30) Gagliardo, Anna; Pollonara, Enrica; Wikelski, Martin
According to the olfactory navigation hypothesis, birds are able to exploit the spatial distribution of environmental odourants to determine the direction of displacement and navigate from non-familiar locations. The so-called “olfactory activation hypothesis” challenged the specific role of olfactory cues in navigation by suggesting that olfactory stimuli only activate a navigational system that is based on non-olfactory cues, predicting that even artificial odourants alone are sufficient to allow unimpaired navigation. In this experiment, we compared tracks of experimental birds exposed to different olfactory stimuli before being made anosmic at the release site prior to release. One group of pigeons was exposed to purified air enriched with artificial odourants, while a second group was exposed to environmental air. The birds stimulated with artificial nonsense odourants displayed several behavioural differences from both untreated controls and anosmic pigeons exposed to environmental air prior to release: nonsense odourants birds were unable to determine the home direction, they mostly flew within a space outside the homeward oriented quadrant, and they flew shorter distances on the day of release. Our data failed to support a mere activational role of olfactory stimuli in navigation, and are consistent with the olfactory navigation hypothesis.
Data from: Pigeon navigation: exposure to environmental odours prior to release is sufficient for homeward orientation, but not for homing
(2016-07-05) Gagliardo, Anna; Pollonara, Enrica; Wikelski, Martin
The role of environmental olfactory information in pigeon navigation has been extensively studied by analysing vanishing bearing distributions and homing performances of homing pigeons subjected to manipulation of their olfactory perception and/or the olfactory information they were exposed to during transportation and at the release site. However, their behaviour during the homing flight remains undocumented. In this experiment we report the analysis of tracks of birds made anosmic at the release site by washing their olfactory mucosa with zinc sulfate. We thus can assess the role of local odours at the release site as well as the role of environmental odours perceived on the way, far from the release site. We observed that pigeons transported and kept at the release site in purified air and made anosmic at the release site were unable to orient towards home and were impaired at homing. By contrast, pigeons allowed to smell environmental odours during transportation and at the release site, although made anosmic prior to release, displayed unimpaired homeward orientation, but nevertheless showed impaired homing performance. These results are consistent with the view that local odour at the release site are critical for determining the direction of displacement (olfactory map) and suggest that pigeons consult the olfactory map also during their homing flight in order to be able to find their way home.
Data from: Pigeons remember visual landmarks after one release and rely upon them more if they are anosmic
(2020-09-24) Gagliardo, Anna; Pollonara, Enrica; Wikelski, Martin
Anosmic birds' homing ability is impaired when challenged to navigate over unfamiliar areas. Nevertheless, anosmic pigeons, Columba livia, show unimpaired navigation when released within a familiar area, suggesting that they may rely on familiar visual landmarks for navigation. However, direct evidence for the reliance on familiar visual landmarks during homing in anosmic birds has never been provided. In this study we tracked pigeons subjected singly to one training flight from each of three locations. Prior to their second release from each site, half of the birds were made anosmic while the others were not manipulated. The level of route fidelity was analysed separately for three phases of the homing process, in which familiar visual cues may have different relevance and may be used within different cognitive strategies: (1) ‘Initial decision making’; (2) ‘En route navigation’; (3) ‘Local navigation around home’. Compared to control birds, the anosmic birds flew significantly closer to previously overflown locations in the ‘En route navigation’ phase, while no difference in route fidelity emerged during phases (1) and (3). Our results showed that a single experience is sufficient for pigeons to learn release site features, and that familiar visual landmarks constitute a critical source of navigational information in olfactorily deprived birds during the homing process.
Data from: Productivity changes in the Mediterranean Sea drive foraging movements of yelkouan shearwater Puffinus yelkouan from the core of its global breeding range
(2021-12-10) Pezzo, Francesco; Zenatello, Marco; Cerritelli, Giulia; Navone, Augusto; Giunchi, Dimitri; Spano, Giovanna; Pollonara, Enrica; Massolo, Alessandro; Gagliardo, Anna; Baccetti, Nicola
Pelagic seabirds are tied to their breeding colonies throughout their long-lasting breeding season, but at the same time, they have to feed in a highly dynamic marine environment where prey abundance and availability rapidly change across space and seasons. Here, we describe the foraging movements of yelkouan shearwater Puffinus yelkouan, a seabird endemic to the Mediterranean Sea that spends its entire life cycle within this enclosed basin and whose future conservation is intimately linked to human-driven and climatic changes affecting the sea. The aim was to understand the main factors underlying the choice of foraging locations during the reproductive phases. A total of 34 foraging trips were obtained from 21 breeding adults tagged and tracked on Tavolara Archipelago (N Sardinia, Italy). This is the largest and most important breeding area for the species, accounting for more than 50% of the world population. The relationships between foraging movements during two different breeding stages and the seasonal changes of primary productivity at sea were modeled. Movements appeared to be addressed toward inshore (<20 km), highly productive, and relatively shallow (<200 m) foraging areas, often in front of river mouths and at great distances from the colony. During incubation, the Bonifacio Strait and other coastal areas close to North and West Sardinia were the most preferred locations (up to 247 km from the colony). During the chick-rearing phase, some individuals reached areas placed at greater distances from the colony (up to 579 km), aiming at food-rich hotspots placed as far north as the Gulf of Lion (France). The need for such long distance and long-lasting foraging trips is hypothesized to be related to unfavorable conditions on the less productive (and already depleted) Sardinian waters.
Data from: Right hemisphere advantage in the development of route fidelity in homing pigeons
(2017-08-01) Pollonara, Enrica; Guilford, Tim; Rossi, Marta; Bingman, Verner P.; Gagliardo, Anna
Several laboratory studies have revealed functional hemispheric lateralization in birds performing visual tasks. However, the role of functional brain asymmetries in spatial behaviour in natural settings is still poorly investigated. We studied monocularly occluded homing pigeons, Columba livia, to investigate potential differences in the hemispheric control of navigational performance. We GPS-tracked monocularly occluded and control binocular homing pigeons during seven group training releases and a final solitary release from each of two sites. The pigeons were then given one last release from each site after a phase shift of the light-dark cycle under binocular conditions, to distinguish compass-based orientation from landmark-based pilotage. Overall, pigeons homing with the left eye/right hemisphere (RH) displayed a greater fidelity to the familiar space previously experienced than pigeons homing with the right eye/left hemisphere (LH). Another difference between the two monocular groups is that LH pigeons were more likely than RH pigeons to fly with other pigeons during the group training releases. The data support the hypothesis that the left eye/right hemisphere plays a more substantial role as pigeons develop fidelity to certain routes to home from familiar release sites, an enhanced fidelity that may be supported by superior memory for familiar landmarks.
Data from: Right hemisphere advantage in the development of route fidelity in homing pigeons
(2017-01-02) Pollonara, Enrica; Guilford, Tim; Rossi, Marta; Bingman, Verner P.; Gagliardo, Anna
NOTE: A corrected version of this dataset is available. See doi:10.5441/001/1.73h2s043. ABSTRACT: Several laboratory studies have revealed functional hemispheric lateralization in birds performing visual tasks. However, the role of functional brain asymmetries in spatial behaviour in natural settings is still poorly investigated. We studied monocularly occluded homing pigeons, Columba livia, to investigate potential differences in the hemispheric control of navigational performance. We GPS-tracked monocularly occluded and control binocular homing pigeons during seven group training releases and a final solitary release from each of two sites. The pigeons were then given one last release from each site after a phase shift of the light-dark cycle under binocular conditions, to distinguish compass-based orientation from landmark-based pilotage. Overall, pigeons homing with the left eye/right hemisphere (RH) displayed a greater fidelity to the familiar space previously experienced than pigeons homing with the right eye/left hemisphere (LH). Another difference between the two monocular groups is that LH pigeons were more likely than RH pigeons to fly with other pigeons during the group training releases. The data support the hypothesis that the left eye/right hemisphere plays a more substantial role as pigeons develop fidelity to certain routes to home from familiar release sites, an enhanced fidelity that may be supported by superior memory for familiar landmarks.
Data from: Study "LifeTrack White Stork Sicily"
(2021-12-10) Grasso, Rosario; Gagliardo, Anna; Zafarana, Manuel; Mueller, Inge; Schmid, Heidi; Fiedler, Wolfgang; Wikelski, Martin
1. Quantifying movement and demographic events of free-ranging animals is fundamental to studying their ecology, evolution and conservation. Technological advances have led to an explosion in sensor-based methods for remotely observing these phenomena. This transition to big data creates new challenges for data management, analysis and collaboration. 2. We present the Movebank ecosystem of tools used by thousands of researchers to collect, manage, share, visualize, analyse and archive their animal tracking and other animal-borne sensor data. Users add sensor data through file uploads or live data streams and further organize and complete quality control within the Movebank system. All data are harmonized to a data model and vocabulary. The public can discover, view and download data for which they have been given access to through the website, the Animal Tracker mobile app or by API. Advanced analysis tools are available through the EnvDATA System, the MoveApps platform and a variety of user-developed applications. Data owners can share studies with select users or the public, with options for embargos, licenses and formal archiving in a data repository. 3. Movebank is used by over 3,100 data owners globally, who manage over 6 billion animal location and sensor measurements across more than 6,500 studies, with thousands of active tags sending over 3 million new data records daily. These data underlie >700 published papers and reports. We present a case study demonstrating the use of Movebank to assess life-history events and demography, and engage with citizen scientists to identify mortalities and causes of death for a migratory bird. 4. A growing number of researchers, government agencies and conservation organizations use Movebank to manage research and conservation projects and to meet legislative requirements. The combination of historic and new data with collaboration tools enables broad comparative analyses and data acquisition and mapping efforts. Movebank offers an integrated system for real-time monitoring of animals at a global scale and represents a digital museum of animal movement and behaviour. Resources and coordination across countries and organizations are needed to ensure that these data, including those that cannot be made public, remain accessible to future generations.
Data from: The homing pigeons’ olfactory map is affected by geographical barriers
(2021-01-19) Gagliardo, Anna; Pollonara, Enrica; Wikelski, Martin
The factors affecting the olfaction-based navigational performances of homing pigeons released at relatively long distance (beyond 100 km from home) has in the past been subject to several investigations both in Germany and Italy using observations of vanishing bearing distributions. These studies highlighted the complexity of long-distance navigation in homing pigeons, which remains a poorly investigated aspect. In this tracking study we report how the homing performances of pigeons housed in Amino (Pisa, Italy) were affected by the presence/absence of a mountain range (the Northern Apennines) interposed between the home and the release site area (release sites: Trans = mountain barrier, Cis = no mountain barrier). We displaced unmanipulated control pigeons, anosmic pigeon, and pigeons transported in purified air to release sites located at a distance ranging between 95 and 246 km from home. There, birds were released without further manipulation. The navigational performances of anosmic pigeons were impaired at both Cis and Trans sites compared to both smelling groups. Both unmanipulated control pigeons and pigeons transported in purified air but allowed to smell environmental air at both the release site and after release displayed unimpaired navigational abilities at the Cis site, but impaired homing success and impaired homeward orientation at the Trans sites. Nevertheless, their homeward component was significantly greater than that of the anosmic birds at both geographical areas. This suggests that the Northern Apennine acts as a geographical barrier affecting the olfactory map accuracy of Amino pigeons, rather than totally reducing its spatial extent.
Data from: True navigation in migrating gulls requires intact olfactory nerves
(2015-11-24) Wikelski, Martin; Arriero, Elena; Gagliardo, Anna; Holland, Richard A.; Huttunen, Markku J.; Juvaste, Risto; Mueller, Inge; Tertitski, Grigori; Thorup, Kasper; Wild, Martin; Alanko, Markku; Bairlein, Franz; Cherenkov, Alexander; Cameron, Alison; Flatz, Reinhard; Hannila, Juhani; Hüppop, Ommo; Kangasniemi, Markku; Kranstauber, Bart; Penttinen, Maija-Liisa; Safi, Kamran; Semashko, Vladimir; Schmid, Heidi; Wistbacka, Ralf
During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated. In this experiment we subjected adult lesser black-backed gulls migrating from their Finnish/Russian breeding grounds (from >60°N) to Africa (to < 5°N) to sensory manipulation, to determine the sensory systems required for navigation. We translocated birds westward (1080 km) or eastward (885 km) to simulate natural navigational challenges. When translocated westwards and outside their migratory corridor birds with olfactory nerve section kept a clear directional preference (southerly) but were unable to compensate for the displacement, while intact birds and gulls with the ophthalmic branch of the trigeminal nerve sectioned oriented towards their population-specific migratory corridor. Thus, air-borne olfactory information seems to be important for migrating gulls to navigate successfully in some circumstances.
Data from: Unilateral hippocampal lesions and the navigational performance of homing pigeons as revealed by GPS-tracking
(2022-12-13) Gagliardo, Anna; Pollonara, Enrica; Bingman, Verner P.; Casini, Giovanni
The left and right hippocampal formation (HF) of the avian brain have been reported to control some different aspects of homing in pigeons. In the current study, we employed GPS-tracking technology and unilateral HF lesions to further explore what if any aspects of a pigeon’s homing flight might be under dominant control by either the left or right HF. Pigeons were released from three locations prior to any experimental manipulation and released repeatedly from the same three sites as sham-lesioned control, right HF-lesioned and left HF-lesioned treatment groups. Analyses of homing performance and virtual vanishing bearings revealed no effect of either lesion treatment. A more in-depth analysis of path efficiency during the initial decision-making, en route and near home phases of a homing flight also revealed no effect of either lesion treatment. A last analysis on the learning and memory for positions along a previously flown route, a proxy for investigating the development of route fidelity, also revealed no effect of either unilateral lesion. However, independent of treatment group, some statistically significant effects were observed with respect to changes in performance across training and the different release sites. The current study revealed no detectable difference between the left and right HF-lesioned pigeons with respect to several navigational parameters of a homing flight. Although in need of supporting experimentation, the results are consistent with the hypothesis that both the left and right HF are similarly able to support several aspects of homing pigeon navigation.

Browsing by Author "Gagliardo, Anna"

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