Avocetta
type: channel
description: Avocetta publishes in a variety of ornithological fields including ecology, behavioural ecology, ethology, phylogeography, taxonomy, biogeography, and conservation.
publisher: Milano University Press
language: en-US
publication name: Avocetta
issn: 0404-4266
items: Influence of climatic conditions and hazelnut farming on the temporal trends and spatial distribution of waterbirds at wintering grounds
items: High-altitude flight in Black-winged Stilt Himantopus himantopus inferred from GPS tracking and ERA5 wind-field data
items: Perched above the fields: density and habitat use of wintering raptors in an intensive farmland area in northern Italy
items: Diet composition and diversity of the Peregrine Falcon Falco peregrinus over 30 years on coastal Mediterranean islands, France
items: Golden Eagle Breeding Returns to the West Bank, Palestine: Offspring Mortality in Both Attempts
items: Notes on the reproductive biology of the Mediterranean Peregrine Falcon Falco peregrinus brookei in South-Eastern Sicily (Italy)
items: The discovery of a dead Gray Catbird Dumetella carolinensis in the port of Genoa, a first record for Italy
items: Even more generalist: an invasive crayfish as a novel food source for Common Buzzards
items: The Foraging by Great Spotted Cuckoo on the caterpillars of Ocnogyna boeticum
items: Lead in hunting ammunition: what are we waiting for?

Influence of climatic conditions and hazelnut farming on the temporal trends and spatial distribution of waterbirds at wintering grounds
type: item
description: Waterbird distribution in Mediterranean wetlands during winter is influenced by habitat conditions, climate, food availability, and human activities. We analysed count data from the International Waterbird Census (2009–2025) at a volcanic lake in central Italy heavily impacted by intensive hazelnut cultivation. Our goal was to assess spatio-temporal trends of long-distance migratory waterbirds and evaluate the influence of large-scale climate (North Atlantic Oscillation, NAO) and the impact of hazelnut farming near the lake. Temporal trends were analysed using Generalized Additive Models (GAMs), while spatial patterns were assessed with Generalized Linear Models (GLMs) using a negative binomial distribution. Analyses were performed at both species level and by grouping species into taxonomic and trophic categories. In total, 74,207 individuals from 28 species were recorded. Five species showed significant declines, particularly among dabbling and diving ducks, as well as herbivorous and omnivorous birds. These declines may be linked to nutrient enrichment from hazelnut farming, which degrades aquatic vegetation and reduces food availability. Despite overall declines, waterbirds were still found—across most taxonomic groups (except herons) and trophic guilds—along lake shores adjacent to hazelnut orchards. This spatial pattern may reflect the presence of remnant patches of palatable aquatic plants in these areas due to eutrophication. We found no significant relationship between bird abundance and the NAO index, suggesting that local temperature anomalies and habitat degradation may play a more decisive role than broad climatic patterns. Our findings highlight the importance of local environmental conditions, particularly land use practices, in shaping wintering waterbird distribution in Mediterranean wetlands. We encourage the replication of this study across other sites to assess if the impact of hazelnut orchards is circumstantial.
creator: Gianpasquale Chiatante
creator: Giampiero Tirone
creator: Fabio Scarfò
creator: Giuseppe Puddu
creator: David Costantini
rights: Copyright (c) 2026 Gianpasquale Chiatante, Giampiero Tirone, Fabio Scarfò, Giuseppe Puddu, David Costantini https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-06-19
publication date: 2026-06-19
volume: 50
doi: 10.30456/avo.29818

High-altitude flight in Black-winged Stilt Himantopus himantopus inferred from GPS tracking and ERA5 wind-field data
type: item
description: Understanding how migratory birds adjust their flight behaviour to cope with environmental challenges is essential to identify the limits of their aerial performance. Black-winged Stilts Himantopus himantopus are considered medium-distance migrants, but their flight altitude has not been studied in detail. In this study, we explored the potential use of high-altitude flight in this species by analysing GPS tracks from two individuals and combining observed ground speeds with vertical wind profiles derived from ERA5 reanalysis data. In several segments, birds reached ground speeds well above the predicted maximum range speed (Vmr = 50 km/h), which, together with favourable tailwind conditions at higher altitudes, suggests they may have flown at between 2000 and 7200 m. These findings are consistent with the possibility of high-altitude migratory flights in H. himantopus, a strategy that could help reduce the cost of transport or avoid adverse surface conditions. Further studies combining GPS tracking with direct measurements of flight altitude are needed to confirm these patterns and assess their generality across populations.
creator: Samuel Pinya Fernández
rights: Copyright (c) 2026 Samuel Pinya Fernández https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-07-15
publication date: 2026-07-15
volume: 50
doi: 10.30456/avo.30339

Perched above the fields: density and habitat use of wintering raptors in an intensive farmland area in northern Italy
type: item
description: The wintering period represents a critical stage for avian survival and population dynamics. However, systematic monitoring during this phase remains scarce compared to the extensive research dedicated to the reproductive period and migration. To address this gap, we investigated the wintering raptor community in the Parmigiano Reggiano production area in the Province of Parma (northern Italy), a unique agro-ecosystem dominated by perennial forage crops, especially alfalfa Medicago sativa. We conducted roadside car transects during the winter of 2025/2026 to estimate the population density using distance sampling, and to assess the habitat preferences of the two most abundant species: the Common Buzzard Buteo buteo and the Common Kestrel Falco tinnunculus. Survey data indicate a high density for both species, with estimated densities of 2.61 ind./km² (95% CI: 1.71-3.97) for the Common Buzzard and 5.73 ind./km² (95% CI: 4.28-7.67) for the Common Kestrel. The Common Kestrel exhibited a strong roadside bias, requiring left-truncation to obtain unbiased estimates. Furthermore, habitat analysis showed a significant selection for forage crops by the Common Kestrel, confirming the key role of alfalfa in the agricultural matrix. We hypothesize that these densities, among the highest recorded in European lowlands, are driven by the synergy between the extensive availability of favourable habitats (i.e., forage crops) supporting high prey densities, and the increasing frequency of mild winters with no snow cover. This study establishes an important quantitative baseline for future winter monitoring, highlighting the importance of adopting distance sampling methods for effective large-scale bird surveys.
creator: Diego Rastelli
creator: Lara Todeschini
creator: Alessandro Pavesi
rights: Copyright (c) 2026 Diego Rastelli, Lara Todeschini, Alessandro Pavesi https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-07-15
publication date: 2026-07-15
volume: 50
doi: 10.30456/avo.30994

Diet composition and diversity of the Peregrine Falcon Falco peregrinus over 30 years on coastal Mediterranean islands, France
type: item
description: Objectives We aimed to provide a long-term, comprehensive description of Peregrine Falcon Falco peregrinus diet composition and diversity on coastal Mediterranean islands, near a major urban area, at breeding and non-breeding seasons. Methods We identified prey species from 87 remain samples of F. peregrinus preys year-round collected on 6 islands near Marseille, France (1995-2024). Prey relative abundance, biomass, and diversity indices were calculated. Seasonal, spatial, and temporal variations in diversity indices and prey taxa abundances were assessed using Kruskal–Wallis tests and generalized linear models. Results We identified 4,483 prey individuals across 180 species (i.e., species richness), with birds <200 g dominating the diet. Shannon diversity index indicated high diversity, while inverse Simpson index and Pielou’s evenness suggested moderate dominance by a few species. The most consumed taxa were small insectivorous passerines (19% abundance, 4% biomass), followed by Phasianidae (15%, 15%) (mainly Common Quail Coturnix coturnix), Apodidae (14%, 6%), Columbidae (11%, 25%), Turdidae (10%, 8%), and Sturnidae (8%, 6%) (Common Starling Sturnus vulgaris). During the breeding season, species richness and Shannon diversity were higher, while inverse Simpson and evenness were lower; Apodidae, Phasianidae and Columbidae were more consumed, and Turdidae and Sturnidae more abundant in the non-breeding season. Urban vicinity islands showed higher richness and Shannon index but lower evenness than remote and uninhabited islands, with Phasianidae and Columbidae more abundant and Apodidae and small insectivorous passerines less abundant. Temporal trends indicated declines in Common Quail remains over 30 years. Conclusion Our 30-year study provides insights into Peregrine Falcon feeding ecology and highlights the high dietary diversity and trophic flexibility of Peregrine Falcons on Mediterranean coastal islands. Temporal, seasonal, and small-scale variations in the co…
creator: Yves Kayser
creator: Marion Fiorentino
creator: Elie Gaget
creator: Patrick Bayle
rights: Copyright (c) 2026 Yves Kayser, Marion Fiorentino, Elie Gaget, Patrick Bayle https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-07-28
publication date: 2026-07-28
volume: 50
doi: 10.30456/avo.31001

Golden Eagle Breeding Returns to the West Bank, Palestine: Offspring Mortality in Both Attempts
type: item
description: The Golden Eagle Aquila chrysaetos, a globally distributed apex raptor, has long been rare in Palestine. This study reports the first documented breeding attempts in the West Bank in more than four decades. Bi-weekly surveys in Wadi Sa'ir and Al-Kanub Nature Reserve (October 2021–June 2023) revealed one active nest at each site, each containing a single chick that was banded. Both nesting areas were dominated by open grassland. Human disturbance was substantially greater in Wadi Sa'ir, largely driven by nearby human-modified land. Both attempts ultimately failed: the 2022 nestling was illegally taken from its nest, and the 2023 fledgling died after electrocution. Fieldwork in 2024–2025 was halted due to regional instability. We summarize nesting ecology, prey composition, threats, and conservation implications, highlighting the urgent need to protect nest sites and reduce human-related risks to support Golden Eagle persistence in the West Bank.
creator: Saed L. Al Shomali
creator: Elias N. Handal
creator: Mahmood Kolnegari
rights: Copyright (c) 2026 Saed L. Al Shomali, Elias N. Handal, Mahmood Kolnegari https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-06-19
publication date: 2026-06-19
volume: 50
doi: 10.30456/avo.29850

Notes on the reproductive biology of the Mediterranean Peregrine Falcon Falco peregrinus brookei in South-Eastern Sicily (Italy)
type: item
description: The Mediterranean Peregrine Falcon, Falco peregrinus brookei, was studied in the southern area of ​​the Iblei Mountains between 2023 and 2025. The survey was initiated to determine the density and spatial distribution of nesting sites using the Nearest Neighbor Distance (NND) methodology. A density of 1.77 pairs/100 km² was recorded. The distribution of nesting sites in the study area was regular (G test 0.75). The fledging rate (fledged young/nests with fledglings) was 2.37.
creator: Angelo Nardo
creator: Iacopo Clemente Romano
creator: Martina Ursula Veken
rights: Copyright (c) 2026 Angelo Nardo, Iacopo Clemente Romano, Martina Ursula Veken https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-02-18
publication date: 2026-02-18
volume: 50
doi: 10.30456/avo.30025

The discovery of a dead Gray Catbird Dumetella carolinensis in the port of Genoa, a first record for Italy
type: item
description: On November 23rd, 2023, a Gray Catbird Dumetella carolinensis was found dead inside the Genoa Pra’ port terminal. This is the first record for Italy. The bird's condition suggests that death occurred approximately 20 days before it was found. On October 26th, another Gray Catbird was observed on Corvo Island (Azores) along with several other Nearctic species. The meteorological dynamics that affected this last arrival, which occurred on the back of a continuous conveyor belt of westerly winds on October 24th across the Atlantic and an inten-sifying low pressure by 25th, could be at the origin of this exceptional find. The possibilities that the bird may have reached Genoa on its own wings or by ship-assistance are discussed.
creator: Alessandro Ghiggi
rights: Copyright (c) 2026 Alessandro Ghiggi https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-02-24
publication date: 2026-02-24
volume: 50
doi: 10.30456/avo.30142

Even more generalist: an invasive crayfish as a novel food source for Common Buzzards
type: item
description: Generalist predators exploit a wide range of food resources, making them more adaptable. Sometimes, the appearance of a new species can lead to their exploitation, especially when it is abundant. In this sense, Red Swamp Crayfishes Procambarus clarkii, one of the most dangerous freshwater exotic species in the world, are an important food resource for some species in their non-native range. We describe a newly observed behaviour and food source for Common Buzzards Buteo bu-teo in Western Iberia, where Red Swamp Crayfish appear to be a recurrent resource in late summer. The buzzards exhibited riverbank-patrolling behaviour and consumed this crusta-cean alongside other prey species. This behaviour represents the discovery of a new inver-tebrate taxon (Crustacea) in the diet of the Common Buzzard, thereby broadening its known trophic spectrum. Future research should explore whether Common Buzzards exploit sim-ilar resources in other regions, particularly where they may prey on other invasive species.
creator: Jorge Sereno-Cadierno
creator: Diego Lorenzo Fuentes-Lamas
rights: Copyright (c) 2026 Jorge Sereno-Cadierno, Diego Lorenzo Fuentes-Lamas https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-02-23
publication date: 2026-02-23
volume: 50
doi: 10.30456/avo.30145

The Foraging by Great Spotted Cuckoo on the caterpillars of Ocnogyna boeticum
type: item
description: The Great Spotted Cuckoo is primarily known as a specialist predator of lepidopteran larvae, particularly the urticating caterpillars of the Pine Processionary Moth Thaumetopoea pityocampa. This report documents a novel observation of a single Great Spotted Cuckoo individual foraging extensively on larvae of the moth Ocnogyna boeticum in a dehesa ecosystem. Over a ten-hour observation period, the cuckoo completed six distinct foraging sessions, consuming a minimum of 768 caterpillars. The bird demonstrated a clear ability to locate and exploit dense aggregations of the larvae, showing marked plasticity in its foraging behaviour.
creator: Florent Prunier
rights: Copyright (c) 2026 Florent Prunier https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-05-15
publication date: 2026-05-15
volume: 50
doi: 10.30456/avo.31019

Lead in hunting ammunition: what are we waiting for?
type: item
creator: Alessandro Andreotti
creator: Enrico Bassi
creator: Gloria Ramello
rights: Copyright (c) 2026 Alessandro Andreotti, Enrico Bassi, Gloria Ramello https://creativecommons.org/licenses/by-sa/4.0
license: https://creativecommons.org/licenses/by-sa/4.0
date: 2026-05-12
publication date: 2026-05-12
volume: 50
doi: 10.30456/avo.31467