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蜂鸟和喜鸟类（通过鸟类传粉）的花演化出了一种互惠的关系。这些花的花蜜合于鸟类的饮食，它们的颜色亦合于鸟类的视觉，它们的形状则合于鸟的喙。这些花的开放时间还被发现与蜂鸟的繁殖季节相吻合。同与被昆虫传粉密切相关的植物相比，喜鸟类植物的花部特征差异很大。这些花也会较昆虫授粉的同类更华丽、复杂和艳丽。被普遍认为的是，植物首先与昆虫形成共同演化关系，喜鸟类植物在后期分化。从鸟类学到昆虫授粉，并没有多少科学依据支持此分歧中相反的例子。喜鸟类植物花器官表型的多样性和蜜蜂传粉物种花器官表型的相对一致性可以归因于传粉者偏好的转变方向。<ref>{{cite journal |last1=Kay |first1=Kathleen M.|last2=Reeves |first2=Patrick A. |last3=Olmstead |first3=Richard G. |last4=Schemske|first4=Douglas W. |s2cid=2991957|title=Rapid speciation and the evolution of hummingbird pollination in neotropical Costus subgenus Costus (Costaceae): evidence from nrDNA ITS and ETS sequences |journal=American Journal of Botany |date=2005 |volume=92 |issue=11|pages=1899–1910 |doi=10.3732/ajb.92.11.1899 |pmid=21646107|doi-access=free }}</ref>

蜂鸟和喜鸟类（通过鸟类传粉）的花演化出了一种互惠的关系。这些花的花蜜合于鸟类的饮食，它们的颜色亦合于鸟类的视觉，它们的形状则合于鸟的喙。这些花的开放时间还被发现与蜂鸟的繁殖季节相吻合。同与被昆虫传粉密切相关的植物相比，喜鸟类植物的花部特征差异很大。这些花也会较昆虫授粉的同类更华丽、复杂和艳丽。被普遍认为的是，植物首先与昆虫形成共同演化关系，喜鸟类植物在后期分化。从鸟类学到昆虫授粉，并没有多少科学依据支持此分歧中相反的例子。喜鸟类植物花器官表型的多样性和蜜蜂传粉物种花器官表型的相对一致性可以归因于传粉者偏好的转变方向。<ref>{{cite journal |last1=Kay |first1=Kathleen M.|last2=Reeves |first2=Patrick A. |last3=Olmstead |first3=Richard G. |last4=Schemske|first4=Douglas W. |s2cid=2991957|title=Rapid speciation and the evolution of hummingbird pollination in neotropical Costus subgenus Costus (Costaceae): evidence from nrDNA ITS and ETS sequences |journal=American Journal of Botany |date=2005 |volume=92 |issue=11|pages=1899–1910 |doi=10.3732/ajb.92.11.1899 |pmid=21646107|doi-access=free }}</ref>

Flowers have converged to take advantage of similar birds.<ref name="Brown">{{cite journal |title=Convergence, Competition, and Mimicry in a Temperate Community of Hummingbird-Pollinated Flowers|author1=Brown James H. |author2=Kodric-Brown Astrid |s2cid=53604204 |journal=Ecology |year=1979 |volume=60 |issue=5 |pages=1022–1035 |doi=10.2307/1936870|jstor=1936870}}</ref> Flowers compete for pollinators, and adaptations reduce unfavourable effects of this competition. The fact that birds can fly during inclement weather makes them more efficient pollinators where bees and other insects would be inactive. Ornithophily may have arisen for this reason in isolated environments with poor insect colonization or areas with plants which flower in the winter.<ref name="Brown"/><ref>{{cite journal |last1=Cronk |first1=Quentin |last2=Ojeda |first2=Isidro |title=Bird-pollinated flowers in an evolutionary and molecular context |journal=Journal of Experimental Botany |date=2008 |volume=59 |issue=4 |pages=715–727 |doi=10.1093/jxb/ern009|pmid=18326865|doi-access=free }}</ref> Bird-pollinated flowers usually have higher volumes of nectar and higher sugar production than those pollinated by insects.<ref name="Stiles">{{cite journal |title=Geographical Aspects of Bird Flower Coevolution, with Particular Reference to Central America |author=Stiles, F. Gary |journal=Annals of the Missouri Botanical Garden |year=1981 |volume=68 |issue=2 |pages=323–351 |doi=10.2307/2398801|jstor=2398801|url=https://www.biodiversitylibrary.org/part/38387 }}</ref>

Flowers have converged to take advantage of similar birds. Flowers compete for pollinators, and adaptations reduce unfavourable effects of this competition. The fact that birds can fly during inclement weather makes them more efficient pollinators where bees and other insects would be inactive. Ornithophily may have arisen for this reason in isolated environments with poor insect colonization or areas with plants which flower in the winter. Bird-pollinated flowers usually have higher volumes of nectar and higher sugar production than those pollinated by insects.

This meets the birds' high energy requirements, the most important determinants of flower choice.<ref name="Stiles"/> In ''[[Mimulus]]'', an increase in red pigment in petals and flower nectar volume noticeably reduces the proportion of pollination by bees as opposed to hummingbirds; while greater flower surface area increases bee pollination. Therefore, red pigments in the flowers of ''Mimulus cardinalis'' may function primarily to discourage bee visitation.<ref>{{cite journal |last1=Schemske |first1=Douglas W. |last2=Bradshaw |first2=H.D. |title=Pollinator preference and the evolution of floral traits in monkeyflowers (''Mimulus'') |journal=Proceedings of the National Academy of Sciences |date=1999 |volume=96 |issue=21 |pages=11910–11915 |doi=10.1073/pnas.96.21.11910|pmid=10518550 |bibcode=1999PNAS...9611910S |pmc=18386|doi-access=free }}</ref> In ''[[Penstemon]]'', flower traits that discourage bee pollination may be more influential on the flowers' evolutionary change than 'pro-bird' adaptations, but adaptation 'towards' birds and 'away' from bees can happen simultaneously.<ref>{{cite journal |last1=Castellanos|first1=M. C. |last2=Wilson |first2=P. |last3=Thomson |first3=J.D. |title='Anti-bee' and 'pro-bird' changes during the evolution of hummingbird pollination in Penstemon flowers |journal=Journal of Evolutionary Biology |date=2005 |volume=17 |issue=4 |pages=876–885 |doi=10.1111/j.1420-9101.2004.00729.x |pmid=15271088|doi-access=free }}</ref> However, some flowers such as ''[[Heliconia angusta]]'' appear not to be as specifically ornithophilous as had been supposed: the species is occasionally (151 visits in 120 hours of observation) visited by ''[[Trigona]]'' stingless bees. These bees are largely pollen robbers in this case, but may also serve as pollinators.

This meets the birds' high energy requirements, the most important determinants of flower choice. In ''[[Mimulus]]'', an increase in red pigment in petals and flower nectar volume noticeably reduces the proportion of pollination by bees as opposed to hummingbirds; while greater flower surface area increases bee pollination. Therefore, red pigments in the flowers of ''Mimulus cardinalis'' may function primarily to discourage bee visitation. In ''[[Penstemon]]'', flower traits that discourage bee pollination may be more influential on the flowers' evolutionary change than 'pro-bird' adaptations, but adaptation 'towards' birds and 'away' from bees can happen simultaneously. However, some flowers such as ''[[Heliconia angusta]]'' appear not to be as specifically ornithophilous as had been supposed: the species is occasionally (151 visits in 120 hours of observation) visited by ''[[Trigona]]'' stingless bees. These bees are largely pollen robbers in this case, but may also serve as pollinators.

Flowers have converged to take advantage of similar birds. Flowers compete for pollinators, and adaptations reduce unfavourable effects of this competition. The fact that birds can fly during inclement weather makes them more efficient pollinators where bees and other insects would be inactive. Ornithophily may have arisen for this reason in isolated environments with poor insect colonization or areas with plants which flower in the winter. Bird-pollinated flowers usually have higher volumes of nectar and higher sugar production than those pollinated by insects.

Flowers have converged to take advantage of similar birds. Flowers compete for pollinators, and adaptations reduce unfavourable effects of this competition. The fact that birds can fly during inclement weather makes them more efficient pollinators where bees and other insects would be inactive. Ornithophily may have arisen for this reason in isolated environments with poor insect colonization or areas with plants which flower in the winter. Bird-pollinated flowers usually have higher volumes of nectar and higher sugar production than those pollinated by insects.

This meets the birds' high energy requirements, the most important determinants of flower choice. In Mimulus, an increase in red pigment in petals and flower nectar volume noticeably reduces the proportion of pollination by bees as opposed to hummingbirds; while greater flower surface area increases bee pollination. Therefore, red pigments in the flowers of Mimulus cardinalis may function primarily to discourage bee visitation. In Penstemon, flower traits that discourage bee pollination may be more influential on the flowers' evolutionary change than 'pro-bird' adaptations, but adaptation 'towards' birds and 'away' from bees can happen simultaneously. However, some flowers such as Heliconia angusta appear not to be as specifically ornithophilous as had been supposed: the species is occasionally (151 visits in 120 hours of observation) visited by Trigona stingless bees. These bees are largely pollen robbers in this case, but may also serve as pollinators.

This meets the birds' high energy requirements, the most important determinants of flower choice. In Mimulus, an increase in red pigment in petals and flower nectar volume noticeably reduces the proportion of pollination by bees as opposed to hummingbirds; while greater flower surface area increases bee pollination. Therefore, red pigments in the flowers of Mimulus cardinalis may function primarily to discourage bee visitation. In Penstemon, flower traits that discourage bee pollination may be more influential on the flowers' evolutionary change than 'pro-bird' adaptations, but adaptation 'towards' birds and 'away' from bees can happen simultaneously. However, some flowers such as Heliconia angusta appear not to be as specifically ornithophilous as had been supposed: the species is occasionally (151 visits in 120 hours of observation) visited by Trigona stingless bees. These bees are largely pollen robbers in this case, but may also serve as pollinators.对于

花朵聚集在一起，利用同类鸟类的优势。花朵争夺传粉者，适应性减少了这种竞争的不利影响。鸟类可以在恶劣天气下飞行，这一事实使它们在蜜蜂和其他昆虫不活跃的地方成为更有效的授粉者。由于这个原因，鸟食现象可能出现在孤立的环境中，这些环境中的昆虫定居能力很差，或者在冬天有植物开花的地方。鸟类传粉的花朵通常比昆虫传粉的花朵有更多的花蜜和更高的糖分产量。这符合鸟类的高能量需求，最重要的决定因素花的选择。在蜜环菌中，花瓣中红色素的增加和花蜜体积的增加明显减少了蜜蜂授粉的比例，而蜂鸟则相反; 同时花朵表面积的增加增加了蜜蜂授粉。因此，红雀花中的红色色素可能主要起到抑制蜜蜂拜访的作用。在 Penstemon，阻碍蜜蜂授粉的花朵特征可能比“支持鸟类”的适应性对花朵进化变化的影响更大，但是“适应”鸟类和“远离”蜜蜂的适应性变化可以同时发生。然而，一些花，如棉铃虫似乎并不像人们想象的那样特别喜好鸟类: 这个物种偶尔(在120小时的观察中造访了151次)被无刺的 Trigona 蜜蜂采访。在这种情况下，这些蜜蜂大部分是花粉盗窃者，但也可能充当传粉者。<ref>{{cite journal |last1=Stein |first1=Katharina |last2=Hensen |first2=Isabell |title=Potential Pollinators and Robbers: A Study of the Floral Visitors of Heliconia Angusta (Heliconiaceae) And Their Behaviour |journal=Journal of Pollination Ecology |date=2011 |volume=4 |issue=6 |pages=39–47|doi=10.26786/1920-7603(2011)7|doi-access=free }}</ref>

花朵聚集在一起以利用同类鸟的优势。<ref name="Brown">{{cite journal |title=Convergence, Competition, and Mimicry in a Temperate Community of Hummingbird-Pollinated Flowers|author1=Brown James H. |author2=Kodric-Brown Astrid |s2cid=53604204 |journal=Ecology |year=1979 |volume=60 |issue=5 |pages=1022–1035 |doi=10.2307/1936870|jstor=1936870}}</ref>花朵为了传粉者而相互竞争，而适应性减少了这种竞争的不利影响。鸟类可以在恶劣天气下飞行，这一事实使它们在蜜蜂和其他昆虫不活跃的地方成为更有效的授粉者。由于这个原因，鸟媒花在处在昆虫定居或植物较少的孤立环境中的冬季开放的花朵中更容易会出现。<ref name="Brown" /><ref>{{cite journal |last1=Cronk |first1=Quentin |last2=Ojeda |first2=Isidro |title=Bird-pollinated flowers in an evolutionary and molecular context |journal=Journal of Experimental Botany |date=2008 |volume=59 |issue=4 |pages=715–727 |doi=10.1093/jxb/ern009|pmid=18326865|doi-access=free }}</ref>鸟类传粉的花朵通常比昆虫传粉的花朵有更多的花蜜和更高的糖分产量。<ref name="Stiles">{{cite journal |title=Geographical Aspects of Bird Flower Coevolution, with Particular Reference to Central America |author=Stiles, F. Gary |journal=Annals of the Missouri Botanical Garden |year=1981 |volume=68 |issue=2 |pages=323–351 |doi=10.2307/2398801|jstor=2398801|url=https://www.biodiversitylibrary.org/part/38387 }}</ref>这也正迎合了鸟类高能量的需求，作为了花在面临自然选择时最重要的决定因素<ref name="Stiles" />。在''沟酸浆属''中，花瓣中红色素和花蜜产量的增加明显减少了蜜蜂授粉的比例，而对于蜂鸟则相反；同时花朵表面积越大蜜蜂授粉的比例也就越高。因此，红雀花中的红色色素可能主要起到抑制蜜蜂拜访的作用。<ref>{{cite journal |last1=Schemske |first1=Douglas W. |last2=Bradshaw |first2=H.D. |title=Pollinator preference and the evolution of floral traits in monkeyflowers (''Mimulus'') |journal=Proceedings of the National Academy of Sciences |date=1999 |volume=96 |issue=21 |pages=11910–11915 |doi=10.1073/pnas.96.21.11910|pmid=10518550 |bibcode=1999PNAS...9611910S |pmc=18386|doi-access=free }}</ref>在''钓钟柳''中，阻碍蜜蜂授粉的花朵特征可能比“支持鸟类”的适应性对花朵进化变化的影响更大，但是“亲和”鸟类和“疏离”蜜蜂的适应性变化可以同时发生<ref>{{cite journal |last1=Castellanos|first1=M. C. |last2=Wilson |first2=P. |last3=Thomson |first3=J.D. |title='Anti-bee' and 'pro-bird' changes during the evolution of hummingbird pollination in Penstemon flowers |journal=Journal of Evolutionary Biology |date=2005 |volume=17 |issue=4 |pages=876–885 |doi=10.1111/j.1420-9101.2004.00729.x |pmid=15271088|doi-access=free }}</ref>。然而，一些花，如''海里康属的大鹤望兰''似乎并不像人们想象的那样特别喜好鸟类：这个物种偶尔（在120小时的观察中被造访了151次）被无刺的''无刺针属''的蜜蜂拜访。在这种情况下，这些蜜蜂更多是作为了花粉盗窃者，但也可能充当传粉者。<ref>{{cite journal |last1=Stein |first1=Katharina |last2=Hensen |first2=Isabell |title=Potential Pollinators and Robbers: A Study of the Floral Visitors of Heliconia Angusta (Heliconiaceae) And Their Behaviour |journal=Journal of Pollination Ecology |date=2011 |volume=4 |issue=6 |pages=39–47|doi=10.26786/1920-7603(2011)7|doi-access=free }}</ref>

Following their respective breeding seasons, several species of hummingbirds occur at the same locations in [[North America]], and several hummingbird flowers bloom simultaneously in these habitats. These flowers have [[convergent evolution|converged]] to a common [[morphology (biology)|morphology]] and color because these are effective at attracting the birds. Different lengths and curvatures of the [[petal#Corolla|corolla]] tubes can affect the efficiency of extraction in hummingbird species in relation to differences in bill morphology. Tubular flowers force a bird to orient its bill in a particular way when probing the flower, especially when the bill and corolla are both curved. This allows the plant to place [[pollen]] on a certain part of the bird's body, permitting a variety of morphological [[co-adaptation]]s.<ref name="Stiles"/>

Following their respective breeding seasons, several species of hummingbirds occur at the same locations in [[North America]], and several hummingbird flowers bloom simultaneously in these habitats. These flowers have [[convergent evolution|converged]] to a common [[morphology (biology)|morphology]] and color because these are effective at attracting the birds. Different lengths and curvatures of the [[petal#Corolla|corolla]] tubes can affect the efficiency of extraction in hummingbird species in relation to differences in bill morphology. Tubular flowers force a bird to orient its bill in a particular way when probing the flower, especially when the bill and corolla are both curved. This allows the plant to place [[pollen]] on a certain part of the bird's body, permitting a variety of morphological [[co-adaptation]]s.<ref name="Stiles"/>

Following their respective breeding seasons, several species of hummingbirds occur at the same locations in North America, and several hummingbird flowers bloom simultaneously in these habitats. These flowers have converged to a common morphology and color because these are effective at attracting the birds. Different lengths and curvatures of the corolla tubes can affect the efficiency of extraction in hummingbird species in relation to differences in bill morphology. Tubular flowers force a bird to orient its bill in a particular way when probing the flower, especially when the bill and corolla are both curved. This allows the plant to place pollen on a certain part of the bird's body, permitting a variety of morphological co-adaptations.

Following their respective breeding seasons, several species of hummingbirds occur at the same locations in North America, and several hummingbird flowers bloom simultaneously in these habitats. These flowers have converged to a common morphology and color because these are effective at attracting the birds. Different lengths and curvatures of the corolla tubes can affect the efficiency of extraction in hummingbird species in relation to differences in bill morphology. Tubular flowers force a bird to orient its bill in a particular way when probing the flower, especially when the bill and corolla are both curved. This allows the plant to place pollen on a certain part of the bird's body, permitting a variety of morphological co-adaptations.

Ornithophilous flowers need to be conspicuous to birds.<ref name="Stiles"/> Birds have their greatest spectral sensitivity and finest hue discrimination at the red end of the [[visual spectrum]],<ref name="Stiles"/> so red is particularly conspicuous to them. Hummingbirds may also be able to see ultraviolet "colors". The prevalence of ultraviolet patterns and nectar guides in nectar-poor entomophilous (insect-pollinated) flowers warns the bird to avoid these flowers.<ref name="Stiles"/> Each of the two subfamilies of hummingbirds, the [[Phaethornithinae]] (hermits) and the [[Trochilinae]], has evolved in conjunction with a particular set of flowers. Most Phaethornithinae species are associated with large [[monocotyledon]]ous herbs, while the Trochilinae prefer [[dicotyledon]]ous plant species.<ref name="Stiles"/>

Ornithophilous flowers need to be conspicuous to birds.<ref name="Stiles"/> Birds have their greatest spectral sensitivity and finest hue discrimination at the red end of the [[visual spectrum]],<ref name="Stiles"/> so red is particularly conspicuous to them. Hummingbirds may also be able to see ultraviolet "colors". The prevalence of ultraviolet patterns and nectar guides in nectar-poor entomophilous (insect-pollinated) flowers warns the bird to avoid these flowers.<ref name="Stiles"/> Each of the two subfamilies of hummingbirds, the [[Phaethornithinae]] (hermits) and the [[Trochilinae]], has evolved in conjunction with a particular set of flowers. Most Phaethornithinae species are associated with large [[monocotyledon]]ous herbs, while the Trochilinae prefer [[dicotyledon]]ous plant species.<ref name="Stiles"/>