Savi’s Warbler Diet and Size: Feeding Habits, Predators, and Measurements

If you’re bird watching in parts of Eastern or Southern England during the late spring and summer months and you hear a bird that sounds like insects reeling, especially at dusk, there’s a slight possibility that you may have stumbled on the habitat of the Savi’s Warbler. Having said that, there are only an estimated 10 breeding pairs of Savi’s Warblers in the UK and they leave for the warmer climes of Africa as soon as the breeding season is over.

In this article we look at the diet of the Savi’s Warbler as well as their breeding habits, size and weight and much more. Keep reading to find out more.

Table of Contents

The Dietary Habits Of The Savi’s Warbler

Savi’s Warblers feed mainly on insects and other small invertebrates. Their diet is suited to their reed bed and wetland habitat.

What Does A Savi’s Warbler Eat?

Savi’s Warblers eat mainly insects including beetles, flies, moths, butterflies, mayflies, grasshoppers, dragonflies and damselflies. They also eat insect larvae, spiders, snails, worms and slugs.

What To Feed A Baby Savi’s Warbler?

Both parents are involved in feeding the chicks and bring food back to the nest frequently during the day. The chicks are fed on a diet of soft bodied insects that includes caterpillars, worms, slugs and insect larvae.

This diet is carefully chosen to be soft and easy to eat as well as being protein rich. This enables the chicks to grow at a fast rate allowing them to fledge the nest around 12 days after hatching.

Breeding Habits Of Savi’s Warblers

The breeding habits of the Savi’s Warbler are concentrated to areas within their preferred habitats of reed beds and wetlands. Males arrive first and establish a suitable nesting territory.

He will use his distinctive reeling song to mark his territory and attract a mate. The male’s song plays a crucial part in their courtship. He will sing from a hidden perch in the reed beds to attract a female.

He might also perform an aerial display to attract a female by flying up from the reeds and then descending back down in order to display his flying prowess.

Once they form a pair, the female will build the nest which is constructed from grasses, reed stems and other plant materials. The nest is cup shaped and built close to the ground concealed in dense vegetation.

Do Savi’s Warblers Mate For Life?

Savi’s Warblers are generally monogamous during the breeding season with one male and one female forming a season-long pair bond. It is possible in some cases that the pair will reunite the following season but this isn’t the normal behaviour of the Savi’s Warbler.

During the season that the pair are bonded, they will produce one or possibly two broods. The following season both partners will form another season-long partnership with a new mate.

The Size & Weight Of Savi’s Warblers

Now let’s look at the typical size and weight of these fascinating and elusive passerines for the purposes of identification.

How Much Does A Savi’s Warbler Weigh?

The average weight of an adult Savi’s Warbler is around 14.5 to 16.5 grams. There is generally no difference in the weight of male and female birds with the exception of egg bearing females who might put on some weight during this time.

How Big Is A Savi’s Warbler?

An average adult Savi’s Warbler is around 14 to 15 cm long from the tip of their bill to the end of their tail. This is roughly the same size as the Long-Tailed Tit except Savi’s Warblers have a longer wingspan.

The wingspan of the Savi’s Warbler is around 15 to 20 cm. This allows them to manoeuvre through their reed bed or wetland habitat with ease.

Are Savi’s Warblers Under Threat?

Savi’s Warblers are not considered to be under threat globally. In fact the International Union for Conservation of Nature (IUCN) classifies them as a bird of least concern.

The same is true in Europe where the Species of European Conservation Concern (SECC) also classifies the Savi’s Warbler as a bird of least concern. However, these small passerines are a rare sight in the UK with only around 10 breeding pairs spotted each year.

Like many wetland species the Savi’s Warbler does face several potential threats that could impact their population numbers. These threats include; habitat loss due to reed bed degradation and wetland drainage, climate change which could affect water levels and temperature changes, drought, pollution and human disturbance due to recreational activities.

What Eats A Savi’s Warbler?

Savi’s Warblers also face the threat of predators including birds of prey like Sparrowhawks and Owls which will take adults and fledglings. As well as nest predation by other birds like Crows and Magpies and mammals like stoats, weasels and rats.

In some areas both adults, eggs and chicks face the threat of predation from snakes as well.

Savi’s Warblers are elusive, secretive birds and their colouration and markings help to keep them camouflaged in their habitats. They also build well hidden nests which do help to protect them from predators.

However, they still remain under constant threat from predators like many other small bird species.

Where Can I See Savi’s Warblers In The UK?

Savi’s Warblers are a relatively rare sight in the UK and are often only seen as passage migrants or occasional breeders. They mainly breed in Continental Europe but there have been reported sightings in the south and east of England.

The most reported sightings of Savi’s Warblers have been in;

Norfolk

RSPB Strumpshaw Fen
Hickling Broad

Suffolk

RSPB Minsmere

Kent

Stodmarsh National Nature Reserve

East Sussex

Rye Harbour

The best time to spot Savi’s Warblers at one of the above locations is between April and June. You will almost certainly hear them before you see them.

Listen for their distinctive song which sounds similar to that of a grasshopper only slower and with a lower pitch. Look in dense reed beds typically close to lakes, marshes or some rivers.

Frequently Asked Questions

What is a Savi’s warbler’s habitat?

The habitat of the Savi’s Warbler is in dense reed beds, marshes and lagoons.

What do Savi’s Warblers eat?

Savi’s Warblers are insectivores and eat mainly flies, beetles and other flying insects like dragonflies, moths, butterflies, mayflies and damselflies. They will also supplement their diet with slugs, worms and insect larvae.

When can Savi’s Warblers be seen in the UK?

Savi’s Warblers are rare in the UK and are only passage migrants with the occasional breeding pair. They can sometimes be seen between the months of April and June during the breeding and migratory season.