A Glimpse of Bird Behaviour - Birds Feeding

In the series of a glimse of birds behaviour, this article explores about the feeding habbits of different birds.

Different birds have different diet and different mode of feeding. According to their diet, there are differences in their appearances, especially the appearance of their beaks and feet: a sunbird that consumes nectar has a long, curved slender beak, while a fly-catcher that feeds on insects has a smaller, triangular beak; an eagle that uses its feet to capture its prey has well-developed talons when compared to that of an egret.

On the other hand, it can seen quite obviously that a bird’s diet is never unique to that bird alone. There will always be other species of birds who prefer the same diet. Yet, despite this preference, there is no real ’competition’ at the end of which one species emerges as the victor, overshadowing and destroying the other. In fact, such birds usually find a way to thrive in harmony.

How is this possible?

Because, even though several species of birds might prefer the same diet and have similar physical adaptations, their feeding behaviours and pattern of feeding are different. Even among closely related species, there are differences in feeding behaviours, and this allows them to live in harmony. These behavioural differences have evolved to suit the ecological niches occupied by each of the species.

         For example, even in one small area, around one tree, several species of warblers can thrive together, because their niches are different, and hence their feeding behaviours are different. Some may feed closer to the ground, while some feed higher up. There will also be differences in the time of feeding. [Their physical adaptations, (for example, their bills) however, remain similar.]

It is important to note that these niches and adaptations aren’t static. They change to meet the needs of the ecosystem and the climate. Therefore, one bird may not exhibit the exact same feeding behaviour exhibited by another bird of the same species living in a different part of the world (because their ecological niches will be different).

An interesting fact is that even within a species of birds living in a particular region, there can be physical and behavioural differences regarding feeding between male and female birds. For example:

-     In some cormorant species, males are larger and dive longer and deeper to hunt

-     In some birds of prey, the males are smaller and more agile

-     In some hoopoe species, the males have a longer beak that helps them find food beneath the bark.

Although there are many differences between species, we can classify the feeding behaviours into a few major categories. Some such categories are,

•  Ground feeding: The birds prefer to feed near the ground: in the grass, under the bushes, etc. The greater coucal, babbler, and mynah are a few examples for birds with ground feeding behaviour.

• Canopy feeding: The birds feed among the branches of trees. Parrots, orioles, and brown-headed barbet are a few examples.

• Bark feeding: This involves finding food on or beneath the bark of trees. The woodpecker is a great example for this.

•   Aerial feeding: In aerial feeding, the birds, such as swifts and swallows, feed while flying.

•  Predatory feeding (Hunting): There are countless variations in this behaviour. Examples for hunting birds include egrets, eagles, etc.  Some hunters may perch in a high up and then pounce on the prey; some may circle in the air looking for the prey, and then swoop down to grab the prey; some may nosedive at very high speeds to catch their prey. Among water birds, there is yet more variety.

•   Hawking: This is a predatory feeding behaviour that resembles aerial feeding. The birds perch on a high point, and when they spot an insect, they swoop down and catch. Good examples are the paradise flycatcher, bee eater, etc.

A pigeon searching for food in the open ©Bhavana

A Black-rumped flameback woodpecker, searching
 for its food on the bark of the tree ©Bhavana

A glossy ibis, hunting in the water with its long beak ©Bhavana

An eagle with its prey grasped in its claws ©Bhavana

It is important to note that even within these categories, there are many differences. For example:

-     Some birds showing ground feeding behaviour prefer to feed in open areas, while others prefer the sheltered area under bushes.

-     Among predators that prey on aquatic organisms, cormorants dive into the water to catch their prey, while egrets stay above water and use their long beaks to catch their prey.

In addition to these feeding behaviours, they are a few curious, interesting behaviours, which are exhibited by some species of birds.

•  Food storage: This is especially seen in temperate regions, where there is food shortage in certain times of the year. Some birds store food by putting them in hole in the trees (acorn woodpecker), or sticking the seeds under the bark using saliva. Surprisingly, a study has even showed that some birds not only remember where they had stored food, but also what they had stored, and when. This was demonstrated in jays, which went straight to the easily perishable, but tasty wax worms, when they were allowed to return to the early to their site of food storage, and the lasting, but not so tasty peanuts, when they were allowed back late.

•   Using tools: Yes. Tools. One example is the Black breasted buzzard in Australia, which uses stones to crack the tough emu eggs. Another example is the woodpecker finch, which uses a small twig to probe for food.

©Bhavana

 

In the above picture, a female Purple-rumped sunbird, drinking nectar from a flower by piercing the flower petals from behind. This is called ‘nectar theft’, as the birds get the nectar without helping the plant with pollination. 

Our own backyards can give us a great opportunity to observe these feeding behaviours, if only we choose to pay attention. Eventhough we talked about the feeding behaviours of birds, we are not sure about the best food for birds, what to feed small birds and why they like those foods etc. 

 Click here to read about the locomotion of birds

Click here to read about vocalisations of birds

Click here to read about the breeding of birds

Click here to read about Fascinating flight of birds

The next article will discuss the bird behaviours related to breeding.