angelinamart's blog

Lek is an occasion for those single birds that need a mate. Birds like manakin will gather to one place and start to show off their displays in terms of plumage, color, vocalization, or dances. In a lek, the male will perform and the female will follow if they like the performance. It is found that these males that form leks have a innate kinship to group up together to win a female to mate. But in the Wild Turkey it is found that these males will form a kinship to collect females but only one of these males have the privilege to mate with the female they like. The kinship appears to be unfair for those males that are only there to assist the one male. However, this kinship does improve the reproduction to be more efficient than one male trying to mate with their desired female.

Birds are monogamous so to choose a mate must be done carefully. Males and females have their own strategies to attract the mate. Males mostly have physical characteristics that are used for displays. In the red-winged blackbird, males will have a bright red color on the wing. However this is not the part that attract females. The color red is correlated with the food the male eats so if the male has a brighter feather, it means he has more territories. The more territory and resources the male has, the more female will be attracted. It is found that males will fight over territories to display how good quality they have.

There is one hypothesis on how females choose a mate. It is called the "good genes hypothesis" where females will base her mate choice based on how the male looks. So in this case, most males will exhibit flashy exaggerated plumage to attract as much females as possible. The good-gene is not only looking at the brightness of the plumage though. In some birds, these plumage color can depend on their diet so by looking at the plumage, health condition can be observed. To know if the male is healthy and not consumed by parasites, females must have the ability to see if the male has the desirable trait or not is viral.

Birds molt during the warm seasons before the breeding season begins. It usually cost 25% to 40% of the total energy. The new feather production requires large production of proteins so they must eat more than any other season to grow faster. Therefore, molting in the warm season is advantageous because the bird can eat more and molt faster. The American Redstart is a common bird found in North America that is well study for its molting strategy. The male has a bright red orange feathers for the breeding season. They molt right after they care for their young. They migrate so the day to departure the area depends on how fast the male is able to molt into this bright color or not. If the male can leave the young early enough, they succeed to molt in this color, but if they are late, the molting will not be complete. This results the late molting males to have a lower breeding rate than the ones that completed their molting.

Compass and some navigation skills are innate for birds. But there are some other components to help birds to orient themselves. In order to migrate, birds must have landmarks to guide them back home. Birds will remember the sights from the sky and uses that to take them back home. Some water, coastal birds would use flow of water and current to navigate themselves. This is not an inurt characteristic so young birds must learn from the older birds how to remember their route to home. This discovery allowed humans to train pigeons to send letters far away and come back after delivery.

Molting is done in the warm seasons before the breeding season. It usually cost 25 to 40% of the energy. The new feather production requires a lots of proteins so they must eat to grow faster. That is why molting in the warm season is advantageous because the bird can eat more and molt faster. The American Redstart is a common bird in North America that is well study for its molting. The male has a bright red orange feathers that are for the breeding season. They molt right after they care for their young, however, the day to departure the area results if the male is able to molt into this bright color or not. If the male can leave the young early enough, then they succeed to molt in this color, but if they are late, the molting will not be complete. This results the late molting males to have a lower breeding rate than the ones that completed their molting.

There are two types of birds, the one that lives in the same habitat all year around and the ones that migrate seasonally. The common pigeon is one of the famous permanent bird that will not leave their habitat unless their environment drastically lack in food. They complete their life cycle in two places. One to grow their offspring and other to mate. The migratory birds will schedule their reproduction location, non-breeding location, and molting location depending on the time of the year. Most birds will not overlap these times so that they can win the resource competition. If a bird is a migratory one, it has many physiological stress such as weight gain and loss. To travel long distance, it must eat as much as it can to gain twice as much so that they have enough fuel.

Canis latrans, Canis lupus, and Canis lupus familiaris are three different species. According to the article, Yes, eastern coyotes are hybrids, but the ‘coywolf’ is not a thing, by Roland Kays mentions that Canis latrans are hybrid species composed of three genetic swapping among the three types of Canis groups. Each type of them have a separate ratio of how much each gene it is composed of. The article writes that the three species are biologically possible to interbreed with one another but preferably not to mate with each other. I think this is the vital part which supports that these species are no longer the same because within a population, species will not have an urge to kill one another within the group. However, the fact that these three species will exhibit enmity is a strong evidence that they are separate.

Migration and navigation are characteristics that are innate, however, there are some learning components as well. That is why the young must learn the small techniques from the experienced birds to know how to navigate themselves in the air. Birds will use the same route from home to the migration location so through experience, the young bird must follow the route and remember it from heart. Through annual migration, the young will attain migratory tools to improve their navigation and they will less likely be lost. The best example is the Baby Indigo Buntings. They are not capable of navigating themselves from birth. So adults will teach them how to look at the star and orient themselves prior to their first migration. The baby bird will practice navigation one month before departure and learn how to look at the bright starts.

Geomagnetic field is produced by the earth and gravity. The pressure caused by this magnetic field can also help birds to orient. For many years, ornithologists have conducted numerous experiments to see what is the relationship between birds and magnetic field is. Then they have found evidence that in some cases, if the pigeon carried a magnet with them, they cannot orient themselves as they would without a magnetic. From all experiments, it is now known that birds will use this magnetic compass in addition to the sun and stars to navigate itself.