Aquatic Warbler Vs Sedge Warbler: Key Differences Explained

Aquatic Warbler Vs Sedge Warbler: Key Differences Explained

In this article we’re going to take a look at the aquatic warbler and another member of the warbler family, the sedge warbler. In many ways these two birds are very similar which can make it difficult to distinguish between each species.

However, on closer inspection, there are enough differences to make an educated guess between the two. Keep reading to find out more.

Key Takeaways

  • You’re very unlikely to see an aquatic warbler in the UK anywhere but the extreme south of England and only in August or early Autumn.
  • The aquatic warbler has paler feathers and a white/yellow stripe on its head which runs from the beak to the top of the head.
  • The aquatic warbler and sedge warbler have pale breasts with the aquatic warbler having dark streaks on its sides which the sedge warbler doesn’t have.
  • The bird song is similar except the common warble is punctuated with a fast chattering sound on aquatic warblers.
  • Aquatic warbler’s eggs are brown and covered in darker brown spots whereas the sedge warbler’s eggs are a greenish yellow colour with brown spots that look like freckles.

What Is The Difference Between An Aquatic Warbler And A Sedge Warbler

Let’s break down the key differences between the two birds.

Visual Differences

Aquatic Warbler

Aquatic warblers are small to medium sized birds, around the same size as a house sparrow. They have a pale yellow central stripe which runs from its beak to the top of its head which separates its dark brown crown. 

They also have a white/yellow eye stripe, a brown/grey back with dark brown streaks and a pale brown or beige breast with dark streaks on the sides. They also have a flattened forehead which is its most notable feature.

The male and female plumage is very similar making it difficult to tell them apart. The juveniles, once fully fledged, are very similar to the adults except they don’t have the dark spots or streaks on their sides.

Sedge Warbler

Sedge warblers are of a similar size to the aquatic warbler with a dark crown with pale streaks and a pale brown, almost cream eye stripe. They have a pale brown back with darker streaks and a pale creamy breast with no streaks.

Differences In Habitat

One of the main differences between sedge warblers and aquatic warblers is where you’re likely to spot them in the UK. Both of these birds fly in from abroad, however, only sedge warblers actually breed in the UK.

They can be found in marshy, wetland habitats all around the UK and Ireland. Whereas aquatic warblers visit the extreme south of Britain and only in passing on their way back to west Africa where they over winter.

Aquatic warblers visit the UK in August and stay just long enough to eat enough insects to fuel their long flight to Africa. Whereas sedge warblers are here from the spring and all through the summer until they migrate to sub Saharan Africa to over winter.

Bird Calls

One of the ways that these two birds can be distinguished is by their bird calls. The song of the sedge warbler is a pleasant rambling warble which is totally different to the song of the aquatic warbler.

The song of the aquatic warbler on the other hand, is a fast chattering which is interrupted with the typical warble common to the warbler genus.

So, if you hear the common warble which indicates that there are warblers present and you hear it interspersed with a fast chattering, you might get lucky and spot an aquatic warbler.

Having said that, the sedge warbler is adept at mimicking the songs produced by other bird species. But, given that it needs to hear that other song first, you could still get to see an aquatic warbler.

As long as you were looking along the south coast of Britain during August or early autumn.

Size & Weight

The Sedge Warbler and Aquatic Warbler are very close in size and weight. Sedge Warblers typically weigh between 10 and 13g, while Aquatic Warblers range from 10 to 14g. This means Aquatic Warblers can sometimes be slightly heavier.

When it comes to wingspan, Sedge Warblers measure 17-21 cm on average, compared to 16.5-19.5 cm for Aquatic Warblers. So Sedge Warblers tend to have a marginally larger wingspan.

These small differences in weight and wingspan are unlikely to be useful for telling the species apart in the field. The birds are simply too similar in these aspects to use as reliable distinguishing features, but we thought we’d include them as they’re interesting to note.

Nests & Eggs

If you were out walking and you were to stumble upon a cup shaped nest in the reed beds made up from a mixture of plant stems and leaves, spider’s webs and soft plant matter. You might have stumbled on to a warbler’s nest.

However, both aquatic warblers and sedge warblers make similar nests. Of course this is all hypothetical as aquatic warblers don’t breed in the UK. To see aquatic warblers breeding you’d need to go to Poland or Belarus or one of the other mainland European countries where they are prominent.

However, assuming you were in Poland the best way to tell which warbler species the nest belongs to is by the eggs. The eggs of the aquatic warbler are brown and covered in darker brown spots.

Whereas the sedge warbler’s eggs are a greenish yellow colour with brown spots that look like freckles.

However, it is never right to tamper with a bird’s nest whatever species of bird it is.

SEE ALSO: Aquatic Warbler Eggs to Chicks: Hatching, Development, and Fledging

Frequently Asked Questions

How do you identify a Sedge Warbler?

You can identify a sedge warbler quite easily as it is a small, sparrow sized bird with a dark crown with pale streaks and a pale brown, almost cream eye stripe. They have a pale brown back with darker streaks and a pale creamy breast with no streaks.

How do you identify an aquatic warbler?

You can identify an aquatic warbler by its pale yellow central stripe which runs from its beak to the top of its head which separates its dark brown crown. It also has a white/yellow eye stripe, a brown/grey back with dark brown streaks and a pale brown or beige breast with dark streaks on the sides. It also has a flattened forehead which is its most notable feature.

Is a Sedge Warbler rare?

A sedge warbler is a fairly common member of the warbler family with an estimated 15 million birds in Europe.

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