Salida de campo al Castrillo, en la provincia de Zamora, cerca de Toro, los días 19 y 20 de junio de 1952, de la que se anotaron observaciones sobre Hirudo medicinalis (Sanguijuela, Annelida), Tinca tinca (Tenca, Actinopterygii), ranas (sin identificar la especie) y las siguientes aves: Acrocephalus arundinaceus (Carricero tordal), Acrocephalus scirpaceus (Carricero común), Alectoris sp. (Perdiz), Anas platyrhynchos (Ánade azulón), Apus sp. (Vencejo), Ardea cinerea (Garza real), Athene noctua (Mochuelo europeo), Burhinus oedicnemus (Alcaraván común), Buteo buteo (Busardo ratonero), Caprimulgus europaeus (Chotacabras europeo), Carduelis carduelis (Jilguero), Carduelis chloris (Verderón común, llamado Chloris chloris por el autor), Certhia sp. (Agateador), Cettia cetti (Ruiseñor bastardo), Ciconia ciconia (Cigüeña blanca), Circus aeruginosus (Aguilucho lagunero occidental), Columba oenas (Paloma zurita), Columba palumbus (Paloma torcaz), Coracias garrulus (Carraca europea), Corvus corax (Cuervo), Coturnix coturnix (Codorniz común), Cuculus canorus (Cuco común) , Cyanistes caeruleus (Herrerillo común, llamado Parus coeruleus por el autor), Cyanopica cooki (Rabilargo, llamado "Charro" y C. cyana por el autor), Dendrocopos major (Pico picapinos, llamado Dryobates major por el autor), Emberiza sp. (Escribano), Falco subbuteo (Alcotán), Fringilla sp. (Pinzón), Fulica atra (Focha común), Fulica cristata (Focha moruna), Galerida sp. (probablemente, G.malabarica, la Cogujada malabar), Gallinula chloropus (Gallineta común), Hippolais polyglotta (Zarcero común), Hirundo sp. (Golondrina), Ixobrychus minutus (Avetorillo común), Lanius meridionalis (Alcaudón real, llamado L.excubitor por el autor), Lanius senator (Alcaudón común), Lullula arborea (Totovía), Luscinia sp. (Ruiseñor), Merops apiaster (Abejaruco europeo), Miliaria calandra (Triguero, llamada, Emberiza calandra por el autor), Milvus milvus (Milano real), Motacilla alba (Lavandera blanca), Oriolus oriolus (Oropéndola), Otus scops (Autillo europeo), Parus major (Carbonero común), Passer domesticus (Gorrión domestico), Petronia petronia (Gorrión chillón), Phoenicurus ochruros (Colirrojo tizón), Phoenicurus phoenicurus (Colirrojo real), Pica pica (Urraca, llamada "marica" por el autor), Saxicola torquata (Tarabilla común), Serinus serinus (Verdecillo), Streptopelia sp. (Tórtola), Sturnus unicolor (Estornino negro), Sylvia hortensis (Curruca mirlona), Tachybaptus ruficollis (Zampullín común, llamado Podiceps ruficollis por el autor), Turdus philomelos (Zorzal común, actualmente sinónimo de T.ericetorum o T.muscicus), Tyto alba (Lechuza común) y Upupa epops (Abubilla). Se incluyen varias ilustraciones a bolígrafo sobre Fulica atra. Joaquín Santos, colaborador del autor, era el propietario de dicho Castrillo., Field trip to the Castillo (Castle), in the province of Zamora, close to the village of Toro, the 19th and 20th of June of 1952, of which there were noted observations about Hirudo medicinalis (European Medical Leech, Annelida), Tinca tinca (Tench, Actinopterygii), frogs (without identifying the species) and the following birds: Acrocephalus arundinaceus (Great Reed-warbler), Acrocephalus scirpaceus (Reed Warbler), Alectoris sp. (Partridge), Anas platyrhynchos (Mallard), Apus sp. (Swift), Ardea cinerea (Grey Heron), Athene noctua (Little Owl), Burhinus oedicnemus (Eurasian Thick-Knee), Buteo buteo (Common Buzzard), Caprimulgus europaeus (Eurasian Nightjar), Carduelis carduelis (European Goldfinch), Carduelis chloris (European Greenfinch, refered as Chloris chloris by the author), Certhia sp. (Tree-creeper), Cettia cetti (Cetti´s Warbler), Ciconia ciconia (White Stork), Circus aeruginosus (Western Marsh-Harrier), Columba oenas (Stock Pigeon), Columba palumbus (Common Wood-pigeon), Coracias garrulus (European Roller), Corvus corax (Common Raven), Coturnix coturnix (Common Quail), Cuculus canorus (Common Cuckoo), Cyanistes caeruleus (Blue Tit, refered as Parus coeruleus by the author), Cyanopica cooki (Azure-winged Magpie, refered as C. cyana by the author), Dendrocopos major (Great Spotted Woodpecker, refered as Dryobates major by the author), Emberiza sp. (Bunting), Falco subbuteo (Eurasian Hobby), Fringilla sp. (Chaffinch), Fulica atra (Common Coot), Fulica cristata (Red-knobbed Coot), Galerida sp. (possibly, G.malabarica, the Malabar Lark), Gallinula chloropus (Common Moorhen), Hippolais polyglotta (Melodius Warbler), Hirundo sp. (Swallow), Ixobrychus minutus (Little Bittern), Lanius meridionalis (Great Grey Shrike, refered as L.excubitor by the author), Lanius senator (Woodchat Shrike), Lullula arborea (Wood Lark), Luscinia sp. (Nightingale), Merops apiaster (European Bee-eater), Miliaria calandra (Corn Bunting, refered as Emberiza calandra by the author), Milvus milvus (Red Kite), Motacilla alba (White Wagtail), Oriolus oriolus (Eurasian Golden-oriole), Otus scops (Common Scops-owl), Parus major (Great Tit), Passer domesticus (House Sparrow), Petronia petronia (Rock Sparrow), Phoenicurus ochruros (Black Redstart), Phoenicurus phoenicurus (Common Redstart), Pica pica (Black-billed Magpie), Saxicola torquata (African Stonechat), Serinus serinus (European Serin), Streptopelia sp. (Turtle-dove), Sturnus unicolor (Spotless Starling), Sylvia hortensis (Orphean Warbler), Tachybaptus ruficollis (Little Greebe, refered as Pocideps ruficollis by the author), Turdus philomelos (Song Thrush, currently synonymous of T.ericetorum or T.muscicus), Tyto alba (Barn Owl) and Upupa epops (Eurasia Hoopoe). Some pen illustrations about Fulica atra are also included. Joaquín Santo, a contributor to the author, was the owner of the Castrillo.