"Believers in evolution" are also known as "thinkers". They think about the theory of evolution and accept it based on the evidence. In this case they "think" that the evolution of well endowed wattles provides an additional sexual attractiveness to mating pairs. This results in more successful matings and more offspring, compared to less well endowed wattles. More offspring with well endowed wattles again mate more successfully and pass on those genes to the next generations. Nothing "superfluous" about it!

Inca terns live along the Pacific coast of South America, from northern Peru to south and central Chile. They are surface feeders feeding mainly on small fish like anchovies but also on crustaceans. They often follow fishing boats and surfacing sea lions looking for scraps. Although they are not listed as endangered or threatened in the wild, they are listed as a PMP (population management program) for captive populations.

Inca tern by Paul Sager, on Flickr


The Golden-breasted Starling's diet is composed almost entirely of insects. Adult birds catch insects in flight and dig up termite mounds to find prey.

Golden-breasted starling


The images shared in this post come from the Lincoln Park Zoo in Chicago, Illinois in July 2021, after the zoo reopened from an extended pandemic closure. The Canon FD 500mm f/4.5L was extended by the Canon Extender FD 1.4X, creating a 700mm configuration. All images were captured in RAW using a Sony a7II mirrorless body mounted to a tripod. The image files were processed using Adobe Lightroom and Topaz DeNoise v6.

'Duck' is the common name for a large number of species in the waterfowl family Anatidae which also includes swans and geese. Ducks are mostly aquatic birds, mostly smaller than the swans and geese, and may be found in both fresh water and sea water. Ducks are divided among several subfamilies in the family Anatidae; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species) but a form a 'taxon', since swans and geese are not considered ducks. Whistling ducks are found in the tropics and subtropics. As their name implies, they have distinctive whistling calls. They have long legs and necks, and are very gregarious, flying to and from night-time roosts in large flocks.

Whistling Duck


Even though masked lapwings tend to avoid humans, many live near urban areas. They nest in unusual places, such as building roofs, school playgrounds, golf courses, gardens, and more. Nests are usually either a scratch on the ground or a small mound of grass and debris. Masked lapwings are unmistakable thanks to their large yellow wattles.

Masked Lapwing


Nicobar pigeons have a gizzard, a muscular organ used for grinding food, that allows them to digest hard nuts that humans often open with a hammer.

Nicobar Pigeon

Indeed that is thinking, good to see that ! "just as successful" can be debated, but I won't. But in all cases there are random variations within a species. Evolution seizes on those variations. Those that enhance the survivability of individuals within a species are perpetuated and those variations which do not enhance survivability (including reproductive success) are not perpetuated. It's pretty straight forward on the surface and very complicated when you look below the surface. Those are my THOUGHTS on the subject
Apologies to the OP. I won't step on your post any further. Mea Culpa.

Inca terns live along the Pacific coast of South America, from northern Peru to south and central Chile. They are surface feeders feeding mainly on small fish like anchovies but also on crustaceans. They often follow fishing boats and surfacing sea lions looking for scraps. Although they are not listed as endangered or threatened in the wild, they are listed as a PMP (population management program) for captive populations.

Inca tern by Paul Sager, on Flickr


The Golden-breasted Starling's diet is composed almost entirely of insects. Adult birds catch insects in flight and dig up termite mounds to find prey.

Golden-breasted starling


The images shared in this post come from the Lincoln Park Zoo in Chicago, Illinois in July 2021, after the zoo reopened from an extended pandemic closure. The Canon FD 500mm f/4.5L was extended by the Canon Extender FD 1.4X, creating a 700mm configuration. All images were captured in RAW using a Sony a7II mirrorless body mounted to a tripod. The image files were processed using Adobe Lightroom and Topaz DeNoise v6.

'Duck' is the common name for a large number of species in the waterfowl family Anatidae which also includes swans and geese. Ducks are mostly aquatic birds, mostly smaller than the swans and geese, and may be found in both fresh water and sea water. Ducks are divided among several subfamilies in the family Anatidae; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species) but a form a 'taxon', since swans and geese are not considered ducks. Whistling ducks are found in the tropics and subtropics. As their name implies, they have distinctive whistling calls. They have long legs and necks, and are very gregarious, flying to and from night-time roosts in large flocks.

Whistling Duck


Even though masked lapwings tend to avoid humans, many live near urban areas. They nest in unusual places, such as building roofs, school playgrounds, golf courses, gardens, and more. Nests are usually either a scratch on the ground or a small mound of grass and debris. Masked lapwings are unmistakable thanks to their large yellow wattles.

Masked Lapwing


Nicobar pigeons have a gizzard, a muscular organ used for grinding food, that allows them to digest hard nuts that humans often open with a hammer.

Nicobar Pigeon