Giacomo Dell'Omo

ABSTRACT Nella stagione riproduttiva 2012 abbiamo analizzato, attraverso la raccolta di borre e resti di prede, il regime alimentare del Gheppio Falco tinnunculus nella Riserva Naturale di Decima-Malafede (Lazio). La raccolta è stata effettuata ispezionando 20 cassette nido posizionate su tralicci dell’alta tensione di Terna e una torre medievale ristrutturata utilizzata come luogo di nidificazione. Tutti i siti controllati erano inseriti in un contesto tipico della campagna agricola romana. Sono state esaminate 91 borre integre, più numerosi frammenti e resti alimentari, per un totale complessivo di 228 prede. Il 46,3% della biomassa predata è rappresentato da uccelli, la restante parte è distribuita tra mammiferi (27,0%), rettili (19,1%) e insetti (7,6%). L’ampia disponibilità di uccelli legati ad ambienti agricoli e la presenza in tarda primavera di individui appena involati, quindi più inesperti, sono i fattori che hanno probabilmente determinato questo risultato; le preferenze alimentari sono indirizzate principalmente verso i passeriformi di piccole dimensioni, il genere Passer è il più rappresentato (26,8% degli uccelli predati). Tra gli insetti catturati la specie dominante è il Coleottero Pentodon bidens (60,0%), un ruolo importante rivestono anche gli ordini degli Odonati (8,8%) e degli Ortotteri (8,0%). I mammiferi sono rappresentati quasi esclusivamente da Roditori: Microtus savii e, in misura minore, Apodemus sp.; l’apporto trofico dei Soricomorfi è irrilevante (0,4%). I Lacertidi costituiscono l’81,5% dei rettili, le catture sono ripartite tra Podarcis sp. (44,4%) e Lacerta bilineata (37,0%); tra le prede compaiono anche Tarentola mauritanica (1,3%) e Chalcides chalcides (0,9%). I risultati di questa indagine confermano che il Gheppio in ambiente Mediterraneo mostra uno spettro trofico più ampio rispetto ai conspecifici nidificanti in zone a clima continentale, dove i micromammiferi rappresentano le prede più comuni. Il carattere opportunistico del gheppio gli permette di sfruttare le risorse trofiche più abbondanti all'interno del proprio territorio di caccia.

ABSTRACT Shearwaters, like many Petrels use different flight modes. Gliding flight is the most typical flight, allowing consuming a minimum amount of energy. However, birds do also flap when taking off, fishing or manoeuvring and this might add substantial cost to the energetic balance of a foraging trip. The GPS track alone is not sufficient to distinguish different flight modes, as filters on speed thresholds do not reflect the pattern of wing beat. We simultaneously deployed small accelerometers and GPS dataloggers on Scopoli’s shearwaters (Calonectris diomedea) to identify the daily activity budget particularly with regard to the flight pattern. We tracked birds breeding in Linosa island during the chick rearing period at the time when they performed short (one day-long) foraging trips. Using combined data gathered with GPS and accelerometers we identified, within the flight portion of the GPS track, different flying modes used by the birds. Then, we compared the estimated energy consumption among flight modes with the overall dynamic body acceleration (ODBA) to produce time and energetic budgets of the foraging trips.

Highly specialized diving birds display substantial dichotomy in neck length with, for example, cormorants and anhingas having extreme necks, while penguins and auks have minimized necks. We attached acceleration loggers to imperial cormorants <i>Phalacrocorax atriceps</i> and Magellanic penguins <i>Spheniscus magellanicus</i>, both foraging in waters over the Patagonian Shelf, to examine the difference in movement between their respective heads and bodies in an attempt to explain this dichotomy. The penguins had head and body attitudes and movements that broadly concurred throughout all phases of their dives. By contrast, although the cormorants followed this pattern during the descent and ascent phases of dives, during the bottom (foraging) phase of the dive, the head angle differed widely from that of the body and its dynamism (measured using vectorial dynamic acceleration) was over four times greater. A simple model indicated that having the head on an ex...

Datasets as supporting information to article Combined use of tri-axial accelerometers and GPS reveals the flexible foraging strategy of a bird in relation to weather conditions. to be published in Plos ONE. Adress questions to Jesus Hernandez-Pliego: jhpliego@ebd.csic.es

Summary. During spring migration, a few tens of thousands of European Honey-buzzards wintering in sub-Saharan Africa cross the central Mediterranean to reach their breeding grounds in central-eastern Europe. In so doing they concentrate passage through the Sicilian Channel but choose different flyways in response to different wind conditions. This study investigated the influence of local and regional wind conditions on the movement patterns of this species along the Strait of Messina, a migration bottleneck located between eastern Sicily and southern continental Italy where some raptors fall victim to illegal shooting by poachers each spring. Simultaneous observations occurred at four watchpoints, three on the Sicilian side and one on the continental boundary (Calabrian side). Although northwesterly winds prevailed at the Strait during peak migration days, slightly different local patterns of both horizontal and vertical winds at each observation site affected flocking and shaped the passage of raptors through this bottleneck, broadening the migration front. The results confirm that the magnitude of Honey-buzzard spring migration at the Strait is strongly affected by wind patterns in the Sicilian Channel. In particular, migrants concentrate at this bottleneck after crossing the Channel in northwesterly winds the previous day. In conclusion, by interpreting migratory behaviour both at local and regional scales, this work can help to plan more efficient monitoring of Honey-buzzards through the Strait and improving the siting of conservationist efforts. —Agostini, N., Chiatante, G., Gustin, M., Cento, M., von Hardenberg, J., Dell'Omo, G. & Panuccio, M. (2021). Local and regional wind patterns affect spring migration magnitude, flyways and flocking of European Honey-buzzards Pernis apivorus at the Strait of Messina. Ardeola, 68: 373-390.

The European honey buzzard Pernis apivorus is a summer visitor in Europe, wintering mostly in West-central Africa. Previous studies concerning timing of autumn migration in relation to sex groups provided contrasting results. In particular, a field survey made in southern Sweden did not report differences in timing, while a satellite study via GPS tracking on six adults, three males, and three females, revealed that the latter departed earlier. The aim of this 4-year study is to further investigate the timing of autumn migration in this species carrying out observations at the Strait of Messina, a bottleneck located along the Central Mediterranean flyway, between August 10th and September 30th 2016–2019. Adult European honey buzzards concentrated the passage between late August early September, with females passing on average 5 days earlier than males. It is suggested that a different role of sexes concerning exhibition of territorial displays during the late breeding season, would ...

SUMMARYProviding homing pigeons with a 5 min preview of the landscape at familiar sites prior to release reliably improves the birds' subsequent homing speeds. This phenomenon has been taken to suggest that the visual panorama is involved in familiar-site recognition, yet the exact nature of the improvement has never been elucidated. We employed newly developed miniature Global Positioning System (GPS) tracking technology to investigate how access to visual cues prior to release affects pigeons' flight along the length of the homing route. By applying a variety of novel analytical techniques enabled by the high-resolution GPS data (track efficiency, virtual vanishing bearings,orientation threshold), we localised the preview effect to the first 1000 m of the journey. Birds denied preview of a familiar landscape for 5 min before take-off flew an initially more tortuous path, including a high incidence of circling, possibly as part of an information-gathering strategy to determ...

This study was aimed at investigating the behavioral effects of ozone (O3) exposure in CD-1 mice. Pairs of same-sex adult male and female mice were continuously exposed for 13 days to either 0, 0.4, 0.8, or 1.2 ppm O3. The exposure apparatus consisted of a system for O3 production and delivery into four stainless-steel chambers, each equipped to contain up to 24 home cages, with continuous monitoring and recording of concentrations. Acute behavioral changes were assessed during the first hour of O3 exposure without removing animals from the chambers. The onset of exposure produced remarkable behavioral disturbances consisting of a sharp increase of several responses (rearing, sniffing, grooming, feeding, and social interactions) paralleled by a reduction of bar-holding. These changes were rapidly reversed within 1 hour, suggesting that they constituted a response to strong novel stimulation followed by habituation. Subsequently, brief sessions of videorecording of the animals' a...

Gliding speed of raptors was supposed to be influenced by the birds morphology and wea-ther conditions. However, a recent study showed that flight speeds of various gliding raptors con-verge to a narrow range. We compared ground-speed (resulting from gliding and sustained flight) of migrating raptors using a Marine Surveillance Radar set horizontally alongside visual observations. Fieldwork was carried out in spring 2014 in a mountainous area some kilometres inland of the Strait of Messina (Southern Italy). The radar echoes were associated to the bird species and the flock size identified by the observers. The screenshots were processed as video frames with radR 2.5.1 package in R software. RadR allows to assign coordinates and time to the echoes which can then be imported into a GIS software for movement analyses. We compared the ground-speed calculated on 30 tracks of different species of raptors (honey buzzard, Montagu's harrier, marsh harrier and black kite) and found no sig...

ABSTRACT During the last decades there has been a growing number of radar applications for ornithology. In addition to the traditional use for monitoring migrating birds, radars have been used in airports to reduce the potential risk of bird collision with aircrafts and alongpower lines and wind mills for assessing the collision risk with these manmade structures. Radars are useful to detect birds movements beyond the range of binoculars and with low visibility (i.e. at night) and these can be quantified exactly, both at the individual and group level. Here we present four case studies gathered in different Italian areas during the last two years: (i) the daily activity of aquatic birds in Venice lagoon; (ii) departure directions during the spring migration of several raptors species from an island in the central Mediterranean; (iii) the transit of passerine birds over a Mediterranean Island at different times of day and night; and (iv) the daily entrance of shearwaters to their colony and their departure in relation to the moon phase. In all these cases the radar has proved to be a reliable tool for revealing aspects of bird behaviour that could not have been detected by traditional observation methods. The behavior revealed by the radar in the four case studies was in line with what has beenhypothesized, although never directly observed. From the recordings gathered it was possible to obtain detailed quantification of the movements. In the future, such recordings can be used to analyse data more deeply using new analytical tools.

I carotenoidi sono un gruppo di pigmenti sintetizzati esclusivamente da organismi fotosintetici che gli animali possono acquisire esclusivamente attraverso la dieta. I radicali liberi sono invece prodotti metabolici altamente reattivi ritenuti essere la principale causa prossima dell'accumulo di danni ossidativi e dell'invecchiamento nei vertebrati. Gli organismi fronteggiano la generazione di prodotti ossidanti tramite composti antiossidanti di origine endogena (ad es. enzimi) ed esogena (ad es. vitamine e carotenoidi) che hanno la capacita di trasformare i radicali in prodotti meno reattivi. Il bilanciamento tra ossidanti ed antiossidanti determina il grado di stress ossidativo. In questo lavoro abbiamo analizzato I) i tipi ed il livello totale di carotenoidi e II) il bilanciamento tra composti ossidanti (ROMs) ed antiossidanti (OXY) in diverse popolazioni di iguana terrestre (Conolophus subcristatusi, specie endemica delle isole centrali ed occidentali delle isole Galapagos. Questo rettile, quasi esclusivamente erbivoro, e considerata come specie minacciata di estinzione dalla World Conservation Union. L'analisi tramite cromatografia liquida ad alta prestazione ha rivelato la presenza di quattro tipi di carotenoidi, due derivati dalla dieta (luteina e zeaxantina) e due derivati metabolici (anidroluteina e 3'-deidroluteina). La concentrazione totale di carotenoidi ha mostrato differenze tra le popolazioni ed e risultata maggiore nelle femmine. Inoltre, il contenuto di carotenoidi ha mostrato una relazione positiva con un indice di condizione corporea suggerendo l' importanza delle disponibilita trofiche nel determinare la variazione della concentrazione di carotenoidi. Effetti simili sono emersi nei profili ROMs ed OXY. In generale, le femmine hanno mostrato livelli di composti ossidanti ed antiossidanti rispettivamente superiori ed inferiori a quelli dei maschi, risultando in un maggior grado di stress ossidativo. Questo dato pone attenzione sui potenziali effetti negativi che lo stress ossidativo puo avere sulla salute delle femmine ed in ultimo sulla loro fitness.

ABSTRACT We investigated body mass variation during the reproductive season in male and female Scopoli's shearwaters (Calonectris diomedea) breeding in Linosa island, Sicily channel. Birds were weighted in three main periods: i.e. before and during egg-laying (mid May - mid June), around hatching (second half of July) and during the early stages of chick rearing (mid July - mid August). In addition, some measurements were also taken around fledging (second half of October). When possible, the same individuals were weighed repeatedly. Overall, there was a marked between-sex difference in body mass, males weighing on average c.100 g more than females. Body mass was higher in males before the engagement on breeding activities (just after the return from their winter migration) and decreased soon thereafter. Conversely, body mass was lower in females during laying and increased during the initial phase of incubation. No other significant variations on the time course of body mass emerged from the analyses. The between-sex difference in body mass profile could be related to a differential effort during the early phases of the reproductive season.

A high interspecific karyotype variability has been evidenced in birds especially in Falconiformes and Strigiformes. Avian cytogenetic analysis, conventionally used for this study, presents several difficulties. We used flow cytometric analysis in order to obtain further information on the DNA patterns of different species of birds belonging to the above-mentioned orders. Our study was performed on blood samples while chicken erythrocytes and human lymphocytes, with known cytometric DNA content, were used as reference cells. The blood samples of the birds under study were stained, simultaneously to the reference cell, with a lysis-staining buffer containing propidium iodide. The nuclear DNA content of the bird samples was calculated as DNA index in relation to reference cells, and was expressed as nuclear DNA mass in picograms (pg) with respect to the standard value of 7.0 pg per human lymphocyte nucleus. The results obtained showed an interspecific variability of DNA content and evidenced the usefulness of FCM analysis as a rapid and easy tool for studying the DNA pattern of different species of birds. Moreover, our results have confirmed and extended the possibility of sex identification in species of birds characterized by sexual monomorphism by evaluating the small DNA content difference which exists between males and females.

A new battery-operated system based on microchips has been developed for detecting free-moving, wild small mammals. An electronic identification unit connected to a portable data-logger can simultaneously accommodate up to eight detector antennae, which are positioned in the habitat of the species under study. The system can operate even in extreme weather conditions and has the capacity to distinguish and record individual mammals entering burrows or visiting artificial feeding stations. Detection events are stored in a data-logger and subsequently can be edited and analysed by many common software packages. A pilot study tested the system by monitoring the visits of three species of small mammals to artificial feeding stations. Further possible applications are discussed.

Following exposure to ozone (O3, 0.6 ppm) from the beginning of neonatal life until weaning, adult CD-1 mice were tested in swimming navigation, a sensitive indicator for hippocampal damage. Control mice received a sham exposure. All mice were tested at 12-13 weeks of age for their ability to find a submerged platform in a fixed location (acquisition: 18 trials, six trials per day) and for capacity to re-orient towards a new platform position (reversal: 12 trials, six trials per day). Exposure to O3 did not produce any significant impairment of swimming navigation during the acquisition phase while it slightly increased the swimming paths during the last day of the reversal phase. Mice exposed to O3 showed a slightly but significantly higher swimming speed during all the days, which was unrelated to differences in body weight and to navigational performances. Moreover, mice exposed to O3 (with the exception of one animal) had a strong tendency to make turns to the left while the controls, independent of sex, preferred clockwise turns. Data are discussed with respect to possible implications with early CNS and immune alteration leading to behavioral asymmetries at adulthood.

Experiments have shown that homing pigeons are able to develop navigational abilities even if reared and kept confined in an aviary, provided that they are exposed to natural winds. These and other experiments performed on inexperienced birds have shown that previous homing experiences are not necessary to determine the direction of displacement. While the cues used in the map process for orienting at the release site have been extensively investigated, the final step of the homing process has received little attention by researchers. Although there is general agreement on the relevance of visual cues in navigation within the home area, there is a lack of clear evidence. In order to investigate the final step of the homing process, we released pigeons raised under confined conditions and others that had been allowed to fly freely around the loft and compared their flight paths recorded with a Global-Positioning-System logger. Our data show that a limited view of the home area impair...

Individual differences in the extent of the infrapyramidal mossy fiber projection (IIP-MF) correlate with performance in tasks sensitive to hippocampal lesions, notably two-way avoidance, radial maze learning, and swimming navigation. Previous studies of swimming navigation suggested that the capacity of reversal learning and measures of directionality might also be related to asymmetries in the distribution of the IIP-MF. In order to verify these findings, the authors crossed the Collins High- and Low-lateralized mice (known to differ in mossy fiber morphology and brain asymmetries) and obtained a F2-generation characterized by strong individual differences in these traits. Twenty-three (13 females, 10 males) mice were tested during 3 days for acquisition of swimming navigation (16 trials) toward a central platform, and during two days (12 trials) for their capacity of reversal learning toward a shifted platform. Morphometry of Timm-stained hippocampi revealed several, partially independent correlations: Larger IIP-MF projections were associated with prolonged crossing over the former platform position during the entire reversal learning; larger IIP-MF projections on the left were correlated with more precise crossing of the former platform position during the first 45 seconds of reversal learning; both extent and asymmetry of IIP-MF correlated positively with overnight improvement of reversal learning; the size of the entire mossy fiber projection (CA4, suprapyramidal and IIP-MF) correlated positively with the time spent in the platform quadrant and measures of initial orientation during acquisition of the task; and the mice showed an ipsilateral turning bias (spin) toward the side with the larger mossy fiber projection. The authors conclude that an intact hippocampus mediates differential processes underlying swimming navigation, and that left and right subfields may have differential functions.