Birdwatchers, listen up: an animal expert explains the meaning behind the calls and songs of Hong Kong birds

A call is acoustically simpler than a song, and usually acts as a warning or a way to keep in contact with other members of the flock. Songs are more complicated, and involve longer and louder vocalisations with a wider variety of pitch. True songbirds need to learn songs from their parents or siblings. If they are separated at a young age and kept alone, they may not be able to sing when they are adults.

Read on to learn more about the different kinds of calls and songs your pet bird or friendly neighbourhood sparrow might be using.

Also known as “communal noise”, the loud, collective sounds of mynahs can’t be missed even amid the noises of the city’s bustling traffic. At night, these birds usually sleep together in trees for safety, and invite companions and friends to join their roosting site.

In the wild, many young birds depend on their parents for food even weeks or months after leaving the nest. So when these young birds are hungry, they make these calls, which include whines, wheezes and chirps, to get their parents to pay attention to them. This call is usually accompanied by a begging posture – wings drooped and head hunched down.

It’s feeding time if your young pet bird is making these noises, though we strongly do not recommend buying baby birds. If you find them in the wild, it is best to bring them to the Society for the Prevention of Cruelty to Animals (SPCA) or call the Agriculture, Fisheries and Conservation Department (AFCD).

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These loud, raspy calls are usually made by crows. It is a familiar sound in the city, which is home to one-fifth of the world’s collared crows. These birds give off a short, low-pitched caw when they detect danger or birds they do not recognise. It is believed that cawing helps them look more threatening.

But it does not always serve as a warning – crows also caw as a friendly greeting. When they see another crow from the same flock, they will use a call that is less shrill and less repetitive.

Just like its name implies, these piercing calls are used to warn others of danger, such as when they see a predator. Alarm calls are usually loud and can be heard from far away. These short and sharp calls may also be used by aggressive or angry birds to threaten or chase away other birds who are pecking at their food.

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This call is commonly associated with pigeons, but only male pigeons bow their heads and scrape their tail feathers along the ground while doing so. Female pigeons are also generally less vocal than their male counterparts. Male pigeons make these low sounds when defending their territory or when signalling that they are available to mate.

These distinctive sounds are longer and much more elaborate than calls are. Only songbirds can sing because they have highly developed vocal organs that allow them to create a diverse range of notes.

Some of the more common winged vocalists you might hear in Hong Kong include warblers, robins and bulbuls. They sing to attract mates and defend their territory. How the songs sound depends on the species of bird, and they also vary according to the bird’s geographic location.

During breeding season, it is typically the male songbirds who sing to attract mates, and the females are usually the ones choosing the lucky bird who sings best (almost like a singing competition show on television).

Other birds – such as swallows – who are more territorial will sing to alert others of their presence. Just like a sing-off, they judge each other on a number of different criteria including rhythm, tone and pitch, and the one with a weaker song leaves.

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Answers provided by Navid Tam, veterinary assistant at Zodiac Pet and Exotic Hospital in Hong Kong