Azure-winged magpies (Cyanopica cyana) Group 1 | Haidlhof Research Station, University of Vienna and University of Veterinary Medicine Vienna, Austria | Subjects: two females, three males; all birds were adults and parent-raised. Housing: outdoor aviary (5 × 3×3 m), partially covered with a semi-transparent roof; the aviary used fine-grained sand as substrate and was equipped with fixed and swinging branches, live plants, stones, woodchips and gravel for caching food, a birdbath, and other enrichment objects. Feeding: the birds were fed daily with different fruits, insects, and seeds; water and pellets (‘Beo komplet’, NutriBird) were provided ad libitum; vitamin supplements and meat or egg were provided every second week. | Apr – Nov 2015; re-test: Apr 2016 | All animal care and data collection protocols were approved by the Animal Welfare Board of the Faculty of Life Sciences, University of Vienna (permit no. 2016–008). |
Azure-winged magpies (Cyanopica cyana) Group 2 | Animal Care Facility of the Department of Cognitive Biology, University of Vienna, Austria | Subjects: two adult females, one adult male, one juvenile female (<1 year old); all birds were parent-raised. one additional juvenile bird was housed in the same aviary, but never participated in the experiment due to physical impairments. Housing: outdoor aviary (6 × 3×3 m), fully covered with a semi-transparent roof; for equipment see group 1. Feeding: see group 1 | Nov 2015 – Apr 2016; re-test: May 2016 | All animal care and data collection protocols were approved by the Animal Welfare Board of the Faculty of Life Sciences, University of Vienna (permit no. 2016–008). |
Carrion crows (Corvus corone) | Haidlhof research station, University of Vienna and university of veterinary medicine vienna, Austria | Subjects: four females, two males; all birds were adults and hand-raised. By appearance, the crows were either carrion crows or hybrids of carrion and hooded crows, reflecting the hybridization belt in Europe. Both species have highly similar life histories and are often considered to belong to one species complex (Vijay et al., 2016). Housing: the aviary comprised a large outdoor part (12 × 9 × 5 m) and two adjacent roofed experimental compartments (3 × 4 × 5 m each); the aviary used coarse sand as substrate and was equipped with fixed and swinging branches, live plants, stones, woodchips and gravel for caching food, several birdbaths, and other enrichment objects. Feeding: the birds were fed a diverse diet containing meat, milk products, cereal, vegetables, and fruit twice a day; water was provided ad libitum. | Oct 2015 – May 2016; re-test: Jul 2016 | All animal care and data collection protocols were approved by the Animal welfare board of the faculty of life sciences, University of Vienna (permit no. 2016–017). |
Common ravens (Corvus corax) | Haidlhof Research Station, University of Vienna and University of Veterinary Medicine Vienna, Austria | Subjects: three adult birds (>4 years old; 1F/2M), six subadult birds (2 years old; 4F/2M); all birds were hand-raised. Housing: large outdoor aviary (15 × 15×5 m) that could be divided into several compartments; equipment see carrion crows. Feeding: see carrion crows. | May – Oct 2016; re-test: Nov 2016 | All animal care and data collection protocols were approved by the Animal Welfare Board of the Faculty of Life Sciences, University of Vienna (permit no. 2016–017). |
Large-billed crows (Corvus macrorhynchos) | Tsukuba Field Station, Keio University, Japan | Subjects: nine sub-adult birds (all were 3 years old; 4F and 5M); all birds were parent-raised and born in the wild. They were caught as free-floating yearlings in the wild and group-housed thereafter. Housing: outdoor aviary (10 × 10 × 3 m) that could be divided four experimental compartments (5 × 5×3 m); the aviary used coarse sand as substrate and was equipped with large branches, a water pool for bathing and other enrichment objects. Feeding: Dairy diet consisted of dog food, meat, eggs, dried fruits. Water was available ad libitum. | May – Jul 2016; re-test: Dec 2016 | Animal Care and Use Committee of Keio University (no. 16059) |
New-Caledonian crows (Corvus moneduloides) Group 1 | La Foa, Province Sud, New Caledonia | Subjects: two adult birds (>3 years old; 1F and 1M) and one juvenile bird (1 st year; M); family group; all were wild caught, temporarily housed and released in the wild. Housing: Crows were housed in an outdoors aviary for temporary behavioral research purposes before being released back into the wild. Feeding: Daily diet consisted of meat, dog food, eggs, and fresh fruit, with water available ad libitum. | Jun – Jul 2017 | University of Auckland Animal Ethics Committee (reference no. 001823). |
New-Caledonian crows (Corvus moneduloides) Group 2 | La Foa, Province Sud, New Caledonia | Subjects: one adult bird (>3 years old; M) and one juvenile bird (1 st year; M); father and son dyad; both were wild caught, temporarily housed and released in the wild. Housing: see group 1 Feeding: see group 1 | May – Jul 2016 | University of Auckland Animal Ethics Committee (reference no. 001823). |
Rooks (Corvus frugilegus) | ‘Eulen- und Greifvogelstation’, Haringsee, Austria | Subjects: 10 adult birds (5F/5M), two subadult birds (1F/1M); all birds were parent-raised and born in the wild. Housing: outdoor aviary (3.3 × 7.4 × 3.1 m) with a roofed platform (3.3 × 1.1 m); the aviary used soil and bark chips as substrate and was equipped with large branches, a water pool for bathing and other enrichment objects. Feeding: the birds were fed on a daily basis with cereals, dried mealworms, minced meat mixed with calcium carbonate and small pieces of scrambled eggs; water was provided ad libitum; nuts and chicks were provided several times a week. | May 2016 – Mar 2017; re-test: Jun 2017 | All animal care and data collection protocols were approved by the Animal Welfare Board of the Faculty of Life Sciences, University of Vienna (permit no. 2016–017). |
Siberian jays (Perisoreus infaustus) Group 1 | Wild population, studied near Arvidsjaur, Swedish Lapland (65°40 N, 19°0 E) | Subjects: male breeder, two non-breeders born in spring 2017, two juveniles born in spring 2018; one subject did not participate in phase 4; all individuals are members of a wild group of Siberian jays, part of a long-term study on individually color-ringed Siberian jays (see Ekman & Griesser 2016). Living area: The study was carried out in a natural setting in a wild population, thus the birds required no care. The apparatus was placed within the focal group’s territory. We provided less preferred food (pig fat) on a standardized feeding device on the side of the experimental apparatus to keep the group near the apparatus. | Sept – Oct 2018 (Experiments were carried out when the birds engage in storing food for winter) | Experiments approved by Umea ethics board, A39-15. Ringing under the license of the Swedish Museum of Natural History. |
Siberian jays (Perisoreus infaustus) Group 2 | Wild population, studied near Arvidsjaur, Swedish Lapland (65°40 N, 19°0 E) | Subjects: male and female breeder, one juvenile born spring 2018. Living area: See above for details. | Sept – Oct 2018 (Experiments were carried out when the birds engage in storing food for winter) | Experiments approved by Umea ethics board, A39-15. Ringing under the license of the Swedish Museum of Natural History. |
Eurasian jackdaws (Corvus monedula) | Comparative Cognition Research Group of the Max-Plank-Institute for Ornithology in Seewiesen, Germany | Subjects: 7 males and seven females adult birds (>4 years old), most of the birds were hand-raised. one subject (male) participated only in phases 0–2; one subject (female) only participated in phases 0–3. two subjects (1 male and one female) joined the group in June 2017 and participated in phases 3–6. Housing: the birds had access to two aviaries (aviary 1: 15m × 9 m × 2.80 m; aviary 2: 12m × 10 m × 2.80 m) with adjacent experimental compartments. All compartments had natural soil and vegetation, including bushes and small trees, and were equipped with breeding boxes, several birdbaths, and other enrichment objects. Feeding: the birds were fed a diverse diet consisting of meat, insects, curd, rice, cereals and Versele Laga Nutribird Beo pearls, and fruit twice a day; water was provided ad libitum. The food was enriched with mineral and vitamin supplements. | Aug 2016 – Aug 2017; re-test: Sep 2017 | The study followed the protocols of the University of Vienna and followed the guidelines of the Association for the Study of Animal Behaviour and conformed the European and German legalisations and guidelines for the use of animals. All animals were habituated to humans. |