{"id":46145,"date":"2026-05-20T09:51:12","date_gmt":"2026-05-20T07:51:12","guid":{"rendered":"https:\/\/g3-guides.com\/newsletter\/the-great-spotted-cuckoo-also-feeds-on-hairy-caterpillars-ocnogyna-boeticum\/"},"modified":"2026-06-02T23:30:38","modified_gmt":"2026-06-02T21:30:38","slug":"the-great-spotted-cuckoo-also-feeds-on-hairy-caterpillars-ocnogyna-boeticum","status":"publish","type":"oikos_newsletter","link":"https:\/\/g3-guides.com\/en\/newsletter\/the-great-spotted-cuckoo-also-feeds-on-hairy-caterpillars-ocnogyna-boeticum\/","title":{"rendered":"The Great-spotted Cuckoo also feeds on Rambur&#8217;s Winter Webworm (Ocnogyna boeticum)."},"content":{"rendered":"\n<p class=\"is-style-text-subtitle is-style-text-subtitle--1 wp-block-paragraph\">I had the good fortune to observe, from the shelter of a hide in Sierra Morena, a phenomenon worthy of being described&#8230; A Great-spotted Cuckoo (<em>Clamator glandarius<\/em>) recently arrived from its migratory route was filling its crop with the caterpillars that make striking communal nests at the end of winter in the meadows of Andalusia.<\/p>\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" data-src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1066-800x800.jpg\" alt=\"\" class=\"wp-image-46127 lazyload\"><noscript><img decoding=\"async\" width=\"800\" height=\"800\" src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1066-800x800.jpg\" alt=\"\" class=\"wp-image-46127\" srcset=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1066-800x800.jpg 800w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1066-380x380.jpg 380w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1066-150x150.jpg 150w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1066.jpg 900w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/noscript><figcaption class=\"wp-element-caption\">The specimen under study. All photos: Daniel Dow: <a href=\"https:\/\/www.instagram.com\/dans_wildlife_photography_\/\" target=\"_blank\" rel=\"noopener\">Instagram<\/a>. <\/figcaption><\/figure>\n\n<p class=\"wp-block-paragraph\"><strong>ABSTRACT <\/strong>: In its European breeding range, the Great-spotted Cuckoo is known primarily as a specialist predator of Lepidoptera, in particular the urticating caterpillars of the pine processionary moth, <em>Thaumetopoea pityocampa<\/em>. We observed an individual feeding extensively on larvae of the butterfly <em>Ocnogyna boeticum<\/em> (Rambur, 1837) in a dehesa ecosystem, with a count of more than 768 caterpillars ingested. <a href=\"https:\/\/riviste.unimi.it\/index.php\/avocetta\/article\/view\/31019\/26421\" target=\"_blank\" rel=\"noopener\">PDF<\/a> <\/p>\n\n<div style=\"height:50px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" data-src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Hide-en-la-Sierra-de-Andujar-800x600.jpg\" alt=\"\" class=\"wp-image-46124 lazyload\"><noscript><img decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Hide-en-la-Sierra-de-Andujar-800x600.jpg\" alt=\"\" class=\"wp-image-46124\" srcset=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Hide-en-la-Sierra-de-Andujar-800x600.jpg 800w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Hide-en-la-Sierra-de-Andujar-380x285.jpg 380w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Hide-en-la-Sierra-de-Andujar.jpg 900w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/noscript><\/figure>\n\n<p class=\"has-accent-2-color has-text-color has-link-color wp-elements-1 wp-block-paragraph\"><strong>It has given me great satisfaction to publish for the first time in an international ornithological journal, <em>Avoceta <\/em>-the bulletin of the Centro Italiano Studi Ornitologici-. <\/strong><\/p>\n\n<p class=\"wp-block-paragraph\">Unlike other occasions when I devoted much effort to complex sampling campaigns, the pleasure here is all the greater because this time, the study practically ran itself. From the very first moments, I felt it was worth counting the prey ingested. Moreover, we had booked the hide for the whole day, and we had nothing else to do but calmly observe the bird. A long day, certainly, but just a single day in the field. Perhaps my most profitable day as a naturalist.     <\/p>\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" data-src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1064-640x800.jpeg\" alt=\"\" class=\"wp-image-46130 lazyload\"><noscript><img decoding=\"async\" width=\"640\" height=\"800\" src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1064-640x800.jpeg\" alt=\"\" class=\"wp-image-46130\" srcset=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1064-640x800.jpeg 640w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1064-304x380.jpeg 304w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1064.jpeg 720w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/noscript><\/figure>\n\n<div style=\"height:50px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n<p class=\"wp-block-paragraph\">I invite you to read the article, which is freely downloadable. Because, beyond the simple counting of caterpillars \u2014 which have gone from a life in the open air on their webs to a direct incorporation into the bird&#8217;s diet \u2014 this mini-study surprised me by the complexity of the questions it raises. <\/p>\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" data-src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1065_Clamator-glandarius-800x533.jpg\" alt=\"\" class=\"wp-image-46121 lazyload\"><noscript><img decoding=\"async\" width=\"800\" height=\"533\" src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1065_Clamator-glandarius-800x533.jpg\" alt=\"\" class=\"wp-image-46121\" srcset=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1065_Clamator-glandarius-800x533.jpg 800w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1065_Clamator-glandarius-380x253.jpg 380w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/IMG_1065_Clamator-glandarius.jpg 900w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/noscript><\/figure>\n\n<div style=\"height:50px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n<p class=\"wp-block-paragraph\">Firstly, the ability to observe a single individual for an entire day and to document its behaviour very thoroughly; the behaviour of the host corvids present (Eurasian magpies and Iberian azure-winged magpies); the synchronisation between the arrival of the migrant \u2014 very early \u2014 and the hatching of the caterpillars; the possibility that <em>Ocnogyna boeticum<\/em> constitutes an important part of its diet; and the abundance of both the prey and the bird in other Mediterranean regions, such as Cyprus. <\/p>\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" data-src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Figure-2.jpg\" alt=\"\" class=\"wp-image-46136 lazyload\"><noscript><img decoding=\"async\" width=\"900\" height=\"582\" src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Figure-2.jpg\" alt=\"\" class=\"wp-image-46136\" srcset=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Figure-2.jpg 900w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Figure-2-380x246.jpg 380w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/Figure-2-800x517.jpg 800w\" sizes=\"(max-width: 900px) 100vw, 900px\" \/><\/noscript><figcaption class=\"wp-element-caption\">Phenology of Great Spotted Cuckoo and <em>Ocnogyna boeticum<\/em> in Spain. <\/figcaption><\/figure>\n\n<div style=\"height:50px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n<p class=\"is-style-text-subtitle has-accent-2-color has-text-color has-link-color has-satisfy-font-family wp-elements-2 is-style-text-subtitle--2 wp-block-paragraph\"><strong>One fine day in 2026, I officially became an ornithologist. The only catch: now I have to follow the path laid out. <\/strong><\/p>\n\n<p class=\"wp-block-paragraph\">Publishing a natural history article based on pure observation means inscribing oneself in the naturalist tradition at a time when this is becoming increasingly difficult to practice on European wildlife. A particular satisfaction.  <\/p>\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" data-src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/P2183503_Birdwatching-father-and-son-800x600.jpg\" alt=\"\" class=\"wp-image-46139 lazyload\"><noscript><img decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/P2183503_Birdwatching-father-and-son-800x600.jpg\" alt=\"\" class=\"wp-image-46139\" srcset=\"https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/P2183503_Birdwatching-father-and-son-800x600.jpg 800w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/P2183503_Birdwatching-father-and-son-380x285.jpg 380w, https:\/\/g3-guides.com\/wp-content\/uploads\/2026\/05\/P2183503_Birdwatching-father-and-son.jpg 900w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/noscript><\/figure>\n\n<p class=\"wp-block-paragraph\">Acknowledgements: first of all to Daniel and William Dow, with whom we shared a photographic session and who made these observations possible by relying on the G3 guides. It was a pleasure to travel together while maintaining a good atmosphere at all times. To Nick Owens for providing us with information on the diet of the Great Spotted Cuckoo in the United Kingdom. To Guillermo Delgado, manager of Paraje San Gin\u00e9s and the hide in the Sierra de And\u00fajar, a host always attentive and committed to conservation. To Roberto Ambrosini, editor-in-chief of Avoceta, and to the associate reviewers.     <\/p>\n","protected":false},"excerpt":{"rendered":"<p>I had the good fortune to observe, from the shelter of a hide in Sierra Morena, a phenomenon worthy of being described&#8230; A Great-spotted Cuckoo (Clamator glandarius) recently arrived from its migratory route was filling its crop with the caterpillars that make striking communal nests at the end of winter in the meadows of Andalusia. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":46122,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"_joinchat":[]},"categories":[557,597],"class_list":["post-46145","oikos_newsletter","type-oikos_newsletter","status-publish","has-post-thumbnail","hentry","category-scientific-publications","category-birds"],"_links":{"self":[{"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/oikos_newsletter\/46145","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/oikos_newsletter"}],"about":[{"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/types\/oikos_newsletter"}],"author":[{"embeddable":true,"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/comments?post=46145"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/media\/46122"}],"wp:attachment":[{"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/media?parent=46145"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/g3-guides.com\/en\/wp-json\/wp\/v2\/categories?post=46145"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}