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There are over 10,000 different bird species in the world, and they all come in all shapes and sizes. From the tiny hummingbirds to the majestic ostriches and albatrosses, birds are as diverse as any in the animal kingdom.
What birds eat varies from species to species as well. Their diet depends on what’s available in the natural habitat as well as on the changing seasons.
This article dives deep into birds’ diets, specifically on what they eat in the wild.
Are Birds Omnivores?
A vast majority of birds are omnivores. This means that they would eat plant-based materials or meat, depending on what is readily available.
It is important to note that omnivores need to eat both plants and meat in more or less equal quantities to be considered omnivores. As such, those who have a small portion of insects in their diet and have a more plant-based diet may not be classified by some as true omnivores and may be classified as herbivores instead.
Omnivores are usually birds that are resident in the area. They are also much more adaptable to their environment as they have a much wider range of food that can be found. Birds that migrate usually experience a scarcity of food due to the limitations of their diet.
Omnivores usually do not have this limitation caused by the changing season. Their diets may change from one preferred category to another during these times, though, depending on what food sources are abundant during the season. Still, this ability does allow them to stay in one location for the long term.
Examples of birds that are omnivores include:
Omnivores are typically considered to be more hardy than other birds with a more restrictive diet. This is mainly because food scarcity is seldom a reason for dips in their population.
Strictly speaking, true herbivore birds are rare. One such example is the hoatzin, whose digestive systems have actually evolved to accommodate a purely plant-based diet. Essentially, those who only have 10% or less of their diet being animal-based may be considered as herbivores.
Based on this rating, it is assumed that 10% of all known bird species can be classified as herbivores, which is an equal percentage of birds that can be considered carnivores based on this very loose qualification.
Herbivore diets will vary. From fruits, nectar, and seeds, other birds may also eat tree sap, roots, stems, and even bark. Birds can feed on vegetables as well, such as kale, corn, pumpkins, broccoli, and cucumbers.
Herbivore birds can be typically broken down into different categories. However, you should take note that birds can fall into two, three, or even all of these categories:
- Frugivorous (fruits)
- Granivorous (grains and seeds)
- Nectarivorous (nectar from flowers)
- Sapsuckers (sap from trees)
It is hard to determine as to what type of plant-based food different birds will preferentially eat as birds are considered as “opportunistic eaters”. This means that they would eat whatever is available or what looks best for them and then move on.
Herbivores’ choice of food may also be determined by what minerals and nutrients they need at any given time. This is especially true when they are planning to migrate or breed, the latter of which requires them to eat insects or other materials rich in protein despite their largely herbivorous lifestyle.
Examples of birds that are herbivores include:
- Canada geese
- Different types of swans
- Silver teals
- Blue macaws
- Evening grosbeaks
Herbivorous birds often have well-developed gizzards. They also often swallow small stones or pebbles which will stay at the gizzard. This will help break down hard food particles and fibers. This would then be regurgitated or passed along as part of their fecal matter.
Herbivores also have a higher risk of extinction due to climate change and deforestation. They are also the types of birds that are most likely to migrate as their food sources dwindle dramatically during the winter seasons.
A small part of the bird population are carnivores. These birds generally eat different types of meat, ranging from insects, fish, shellfish, other birds, and small mammals. There are also others that eat living animals, those that are close to dying, and even carrion such as roadkill.
For the latter category, vultures and ravens are among the most well-known. Also known as scavengers, they have also been known to perch near animals that are near death and may even peak at them even while they’re still alive. Hawks, terns, and gulls are also known to eat dead flesh.
Like herbivores, birds may be loosely categorized as carnivores. As such, those who have meat as a large part of their diet despite eating a small amount of plant-based matter will be considered as having a generally carnivorous diet. Also, like herbivores, about 10% of the total bird population are carnivores.
Carnivores, compared to other birds, have better-attuned senses, specifically eyesight. Others have heightened senses of smell and hearing as well. Birds that feed on meat also have stronger claws and beaks, the latter of which are mostly curved in shape.
Birds of prey, also called raptors, also typically hunt solo, with very few exceptions. Carnivorous birds are also larger in general and have wide wing spans. Some of the largest ones include harpy eagles, Andean condors, California condors, and the Philippine eagle.
These qualities are found in predatory birds simply because these attributes are most well-suited for a more successful hunt. Some birds of prey even have specialized glands that produce oil that they can use on their feathers to serve as a form of waterproofing. This can allow them to dive underwater and catch fish more effectively.
Examples of birds that are carnivores are:
Larger and more powerful carnivorous birds can attack and lift animals weighing up to 20 pounds. As such, those who own small pets or have newborns should be careful should they live within an area where birds of prey dwell nearby.
How Do Birds’ Diets Change?
A lot of variables can affect a bird’s diet. The timing of these changes can vary and may also be temporary or permanent. How these birds adapt to their changes would be instrumental to their prolonged survival.
Birds change their diets when they are breeding. Birds will eat more insects and other protein sources to ensure an increased number of, and stronger, clutches. Babies from birds that have usually varied diets as adults may be fed by their parents more protein-rich foods as well to ensure better growth.
During migration, the food of choice is fruits and nectar. This is because sugars stored as fat will serve as more efficient fuel sources for the long flight toward their destination. In some cases, many birds can even eat up to two times their body weight to support the energy requirements that they need for their journey.
Birds will also often eat whatever is readily available, especially if their preferred food sources are not available. This holds especially true for migrating birds, and even for residents that experience scarcity of their main foods during the winter or fall season.
During seasons of food scarcity, some birds have also been known to forage and hide food. Crows are a prime example of this. Crows have been known to store excess food such as nuts or seeds under rocks, on rain gutters, and may choose to either share or eat them individually when needed.
Others, on the other hand, have evolved in such a way that they will eat almost literally anything that is available, man-made foods included. This is what makes city birds such as pigeons very acclimated to urban living as they are able to live off garbage, and even manure if their preferred foods are not available.
How Do Birds’ Diets Affect the World?
Where, what, and how much birds eat can affect humans and the world in general. These can be both positive and negative in nature and can be especially seen in the agricultural sector.
Birds that are herbivorous or omnivorous seem to have the largest effect on the world. For one, they share a main food source that is similar to ours, namely fruits and grains. The more they eat, the less there is for us, either for individual or commercial use.
For this reason, many farmers often use pesticides or other means to dissuade birds from feeding on their crops. This affects not only the quality of the crops themselves but can harm birds as well.
Birds can also bring with them diseases that they can transfer to other endemic birds or even humans. They can also upset the balance of a territory’s ecosystem if they are a particularly invasive species.
On a positive note, feeding birds can have a lot of positive effects on the world. For one, they can help remove pests as insects are one of the most destructive forces that can attack crops. They can also eat rats or smaller birds that feed on fruits. Secondly, they can also help propagate plant life in the wild as seeds and spores can be spread to other locations during and after feeding.
Carnivorous birds that feed on carrion also provide an unintentional benefit of removing toxins and pathogens from the environment as dead matter decays. Despite their appearances, these birds of prey do provide a very important service as they help in the prevention of the possible spread of disease.
Human Threats to Birds’ Diets
Humans have, had, and are still changing the way that birds feed. Perhaps the biggest impact of human actions on the bird’s food supply is deforestation. As more forests are being denuded and urbanization has progressed at much faster rates than ever before, trees, plants, insects, and other wildlife become limited.
This affects not only birds that are residents of the area but also migratory birds. As they find less food during their stopovers, they may not have enough energy to fly towards their destination. This would also result in a poorer number of clutches and weaker offspring.
Pesticides, as previously mentioned, are another big factor that causes numerous deaths of birds per year. However, one of the biggest contributing factors that affect birds’ diets may be pollution.
Pollution has both direct and indirect effects. Pollution can affect the landscape of its immediate environment. It also causes climate change that can destroy food sources at much faster rates. It can shorten or alter migratory paths of birds especially if they find a polluted area unsuitable to live on anymore.
Trash can also poison birds. Plastics can trap and drown birds diving for fish in bodies of water. Plastics can also get into their stomachs, blocking their digestive tract and not allowing any food intake until they get malnourished and die. Pigeons also often die by invertedly eating materials that they are not supposed to, such as cigarette butts.
Even the innocent action of building and maintaining a bird feeder can alter birds’ diets. It can change migratory patterns, disrupt endemic species and the fragile prey/predator ecosystem, introduce disease, and even harm the birds stopping over to feed as this can be a hotspot for predators such as cats.
Birds’ diets are as diverse as the species themselves. Like it or not, they are a part of nature’s ecosystem and, as such, a certain balance must always be achieved.
With this, we as humans should always take care to ensure that our flighty friends have ample food to support their population, as their loss will affect us as well.
We should also be mindful of our actions that may affect birds’ natural diet and behavior. Something as simple as having exposed garbage or even inherently good actions such as installing a bird feeder can have negative effects on birds without any purposefully ill intentions on our end.
Perhaps the best thing that we could do as a human race is to live and let live. Make sure that we live with as little an environmental impact as possible. We can plant trees, we can ensure that our immediate surroundings are clean, and we can of course enjoy seeing birds feed and live their hopefully happy and stress-free lives.