{"id":{"repo_id":"oldenburg","oai_identifier":"oai:oops.uni-oldenburg.de:300"},"canonical_url":"https://search.dev.ndltd.org/etd/oldenburg/oai:oops.uni-oldenburg.de:300","repository":{"repo_id":"oldenburg","name":"Carl von Ossietzky Universität Oldenburg","base_url":"http://oops.uni-oldenburg.de/cgi/oai2"},"display":{"title":"The role of fruit colour in avian fruit selection: an objective approach","abstract":"To explain the prevalence of red and black fruits in fruit colour patterns, the following hypotheses were addressed, using reflectance spectra of fruits as colour assessment: 1. Birds prefer red and black fruits, or these hues are cues for food recognition in migrants or fledglings. 2. Fruit colours correlate with chemical compounds. 3. Fruit colours serve as advertisement for ripe fruits. Reflectance spectra are the most objective colour assessment currently possible. Birds show no colour preference, naive blackcaps prefer red fruits and might have a genetic predisposition. Black and white fruits have high tannin content, some red, orange and yellow fruits show high protein contents. The unexplained biological activity of tannins and the unknown avian visual system leave the correlation unclear. Black and red fruits are the most conspicuous fruits. Birds choose more contrasting displays. Thus, conspicuousness influences fruit choice, and fruit colours seem to be an advertisement for ripe fruits.","abstract_html":"To explain the prevalence of red and black fruits in fruit colour patterns, the following hypotheses were addressed, using reflectance spectra of fruits as colour assessment: 1. Birds prefer red and black fruits, or these hues are cues for food recognition in migrants or fledglings. 2. Fruit colours correlate with chemical compounds. 3. Fruit colours serve as advertisement for ripe fruits. Reflectance spectra are the most objective colour assessment currently possible. Birds show no colour preference, naive blackcaps prefer red fruits and might have a genetic predisposition. Black and white fruits have high tannin content, some red, orange and yellow fruits show high protein contents. The unexplained biological activity of tannins and the unknown avian visual system leave the correlation unclear. Black and red fruits are the most conspicuous fruits. Birds choose more contrasting displays. Thus, conspicuousness influences fruit choice, and fruit colours seem to be an advertisement for ripe fruits.","abstract_has_math":false,"creators":["Schmidt, Veronika"],"institution":"Universität Oldenburg","degree_name":null,"degree_level":"thesis.doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002-07-26","date_published":"2002-07-26","updated_at":"2026-07-27T20:27:22Z","subjects":["[Keine Schlagwörter von Autor/in vergeben.]"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://oops.uni-oldenburg.de/300","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Schmidt, Veronika"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:publisher","label":"Institution","values":["BIS der Universität Oldenburg"]},{"key":"dc:type","label":"Dc Type","values":["doctoralThesis"]},{"key":"thesis:degree_level","label":"Degree Level","values":["thesis.doctoral"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Universität Oldenburg"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["[Keine Schlagwörter von Autor/in vergeben.]"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["To explain the prevalence of red and black fruits in fruit colour patterns, the following hypotheses were addressed, using reflectance spectra of fruits as colour assessment: 1. Birds prefer red and black fruits, or these hues are cues for food recognition in migrants or fledglings. 2. Fruit colours correlate with chemical compounds. 3. Fruit colours serve as advertisement for ripe fruits. Reflectance spectra are the most objective colour assessment currently possible. Birds show no colour preference, naive blackcaps prefer red fruits and might have a genetic predisposition. Black and white fruits have high tannin content, some red, orange and yellow fruits show high protein contents. The unexplained biological activity of tannins and the unknown avian visual system leave the correlation unclear. Black and red fruits are the most conspicuous fruits. Birds choose more contrasting displays. Thus, conspicuousness influences fruit choice, and fruit colours seem to be an advertisement for ripe fruits.","Mit Reflektionsspektren von Früchten wurden Hypothesen zur Dominanz roter und schwarzer Früchte in der globalen Fruchtfarbenverteilung untersucht: 1. Vögel präferieren rote und schwarze Früchte, oder die Farbtöne dienen Zugvögeln oder Jungvögeln zur Erkennung geeigneter Nahrung. 2. Fruchtfarben zeigen chemische Inhaltsstoffe an. 3. Fruchtfarben dienen als Fernsignal und kündigen reife Früchte an. Reflektionsspektren stellen die objektivste Farbklassifizierung dar. Vögel präferieren keine Farbe, naive Mönchsgrasmücken wählen rot und verfügen ggf. über eine genetische Prädisposition. Schwarze und weiße Früchte haben hohen Tanningehalt, einige rote, orange und gelbe Früchte hohen Proteingehalt. Die unklare biologische Aktivität der Tannine und das Sehsystem der Vögel lassen den Zusammenhang ungeklärt. Schwarze und rote Früchte sind am auffälligsten. Vögel bevorzugen kontrastreichere Displays, daher beeinflußt Auffälligkeit die Fruchtwahl. Fruchtfarben dienen vermutlich als Fernanzeiger für reife Früchte."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The role of fruit colour in avian fruit selection: an objective approach"]}]}],"canonical_facts":{"dc:creator":["Schmidt, Veronika"],"dc:description.abstract":["To explain the prevalence of red and black fruits in fruit colour patterns, the following hypotheses were addressed, using reflectance spectra of fruits as colour assessment: 1. Birds prefer red and black fruits, or these hues are cues for food recognition in migrants or fledglings. 2. Fruit colours correlate with chemical compounds. 3. Fruit colours serve as advertisement for ripe fruits. Reflectance spectra are the most objective colour assessment currently possible. Birds show no colour preference, naive blackcaps prefer red fruits and might have a genetic predisposition. Black and white fruits have high tannin content, some red, orange and yellow fruits show high protein contents. The unexplained biological activity of tannins and the unknown avian visual system leave the correlation unclear. Black and red fruits are the most conspicuous fruits. Birds choose more contrasting displays. Thus, conspicuousness influences fruit choice, and fruit colours seem to be an advertisement for ripe fruits.","Mit Reflektionsspektren von Früchten wurden Hypothesen zur Dominanz roter und schwarzer Früchte in der globalen Fruchtfarbenverteilung untersucht: 1. Vögel präferieren rote und schwarze Früchte, oder die Farbtöne dienen Zugvögeln oder Jungvögeln zur Erkennung geeigneter Nahrung. 2. Fruchtfarben zeigen chemische Inhaltsstoffe an. 3. Fruchtfarben dienen als Fernsignal und kündigen reife Früchte an. Reflektionsspektren stellen die objektivste Farbklassifizierung dar. Vögel präferieren keine Farbe, naive Mönchsgrasmücken wählen rot und verfügen ggf. über eine genetische Prädisposition. Schwarze und weiße Früchte haben hohen Tanningehalt, einige rote, orange und gelbe Früchte hohen Proteingehalt. Die unklare biologische Aktivität der Tannine und das Sehsystem der Vögel lassen den Zusammenhang ungeklärt. Schwarze und rote Früchte sind am auffälligsten. Vögel bevorzugen kontrastreichere Displays, daher beeinflußt Auffälligkeit die Fruchtwahl. Fruchtfarben dienen vermutlich als Fernanzeiger für reife Früchte."],"dc:format.medium":["application/pdf"],"dc:publisher":["BIS der Universität Oldenburg"],"dc:subject":["[Keine Schlagwörter von Autor/in vergeben.]"],"dc:title":["The role of fruit colour in avian fruit selection: an objective approach"],"dc:type":["doctoralThesis"],"thesis:degree_level":["thesis.doctoral"],"thesis:institution_name":["Universität Oldenburg"]},"updated_at":"2026-07-27T20:27:22Z"}