Uncovering the Willow Tit (Poecile montana): The Expert Excavator

Identification: A Tricky ID

Identifying the Willow Tit relies on a combination of subtle visual cues, habitat, and, most importantly, its distinct vocalizations.

Plumage Details

The Willow Tit has a generally duller appearance than the Marsh Tit. Its cap is a sooty or brownish-black, lacking the distinct gloss of a Marsh Tit's cap, and often appears 'fluffier' or more extensive. The bib under the chin is typically larger, more diffuse, and less neatly defined than a Marsh Tit's. Cheeks are whitish but can appear duskier. A key feature, often visible in good light, is a pale buffish or whitish panel on the closed wing, formed by the pale edges of the secondary feathers; this is generally absent or much less obvious in Marsh Tits. The upperparts are greyish-brown, and underparts are off-white to buff.

Male, Female, and Juvenile Differences

Males and females are virtually indistinguishable in the field. Juveniles are very similar to adults, perhaps with slightly buffer tones and a less defined cap and bib.

Size and Build

• Length: Approximately 11.5-12.5 cm (4.5-4.9 inches).
• Wingspan: Around 17-20.5 cm (6.7-8.1 inches).
• Weight: About 9-12 grams (0.32-0.42 oz).

It often appears slightly larger-headed or more 'bull-necked' than a Marsh Tit, with a slightly longer tail. Its bill is typically all dark and can seem a fraction more robust.

Distinguishing from Marsh Tit (Poecile palustris)

Separating Willow Tit from Marsh Tit is a classic birding challenge. Vocalization is the most reliable method.

• Call: Willow Tit has a distinctive nasal, slightly buzzy "chay-chay-chay" or "eez-eez-eez" call. Marsh Tit has an explosive "pitchoo".
• Song: Willow Tit song is a series of clear, fluting, often melancholic whistles "piu-piu-piu-piu" or "tui-tui-tui". Marsh Tit song is more variable, often a repeated "schip-schip-schip".
• Cap: Willow Tit's cap is dull, sooty black. Marsh Tit's is glossy black.
• Bib: Willow Tit's bib is larger, more diffuse. Marsh Tit's is smaller, neater.
• Wing Panel: Willow Tit often shows a pale panel on the secondaries. Marsh Tit usually lacks this.
• Nesting Behaviour: Willow Tit excavates its own nest hole. Marsh Tit uses existing cavities.
• Head Shape: Willow Tit can appear more 'bull-necked'. Marsh Tit often looks neater.

Habitat & Distribution

The Willow Tit is often found in younger, damper, or more scrubby woodland than the Marsh Tit.

Preferred Habitats

It favours damp deciduous or mixed woodlands, particularly areas with birch, alder, and willow, often along river valleys or heathland edges. It thrives in younger successional woodland, scrubby areas, and conifer plantations with plentiful dead or decaying trees suitable for excavating nest holes. They are less common in mature, closed-canopy oak woodland preferred by Marsh Tits.

Geographic Range

The Willow Tit has a vast Palearctic distribution, found from Britain and Scandinavia across northern and central Europe, and through Siberia to Japan. Several subspecies exist, with some northern forms being notably paler. It is absent from Iberia, Italy, and much of southeastern Europe. Unlike the Marsh Tit, it is found in Ireland (though scarce). Populations are largely resident.

Behaviour: The Nest Digger

The Willow Tit's most remarkable behaviour is its ability to excavate its own nest cavity.

Foraging

They are active foragers, searching for insects, spiders, and seeds among foliage, twigs, and bark. They are agile and will hang from branches. In winter, they are known to cache food, similar to other tits in the Poecile genus.

Nest Excavation

Unlike most other European tits (except the Crested Tit, which also excavates but prefers pine), the Willow Tit almost invariably digs out its own nest chamber. Both sexes contribute to this task, choosing soft, decaying wood in stumps, dead standing trees (snags), or fallen logs. This can take one to three weeks.

Social Interactions

Typically seen in pairs, which remain together on territory year-round. They can be quite shy and elusive. In winter, they may sometimes join mixed-species flocks but are generally less gregarious than some other tits.

Diet & Feeding Habits

The Willow Tit's diet comprises insects in summer and a mix of seeds and invertebrates in winter.

Primary Food Sources

During spring and summer, their diet is dominated by insects (especially caterpillars, aphids, flies) and spiders, crucial for feeding their young. They meticulously search branches and leaves for prey.

Autumn and Winter Diet

In autumn and winter, seeds of various trees (birch, alder) and herbaceous plants become important, supplemented by any available insects and spiders. They will visit garden bird feeders, particularly for sunflower hearts, peanuts, and suet, but are often more wary than other tits.

Nesting & Reproduction: The Excavator

The Willow Tit's dedication to excavating its own nest is a defining characteristic.

Nest Site Selection and Excavation

The pair selects a site in soft, rotting wood – typically a dead birch, alder, or willow stump or snag, often low down. Both birds work to chisel out a deep chamber using their small beaks. The entrance hole is small and neat. This reliance on decaying wood makes them vulnerable to tidy forestry practices that remove such habitat features.

Information on managing woodlands for biodiversity, including retaining deadwood which benefits species like the Willow Tit, can be found on conservation websites such as The Wildlife Trusts' land management pages.

Nest Construction

Inside the excavated cavity, a sparse nest cup is made, typically of wood chips from the excavation, moss, and lined with animal hair or fine plant down. The female usually does most of the lining.

Eggs and Incubation

A clutch usually consists of 6-9 glossy white eggs, finely speckled with reddish-brown. Incubation is by the female for about 13-15 days, during which she is fed by the male.

Raising the Chicks

Both parents feed the young with insects and spiders. The chicks fledge after about 17-19 days. The family group may stay together for a while. Willow Tits usually raise a single brood per year.

Vocalisations: Crucial for Identification

The Willow Tit's calls and song are the most reliable way to separate it from the Marsh Tit.

Song

The song is a series of clear, rather melancholic, fluting whistles, typically on one pitch or slightly descending: "piu-piu-piu-piu" or "tui-tui-tui-tui". It's quite distinctive once learned.

Calls

The most characteristic call is a nasal, somewhat buzzy "chay-chay-chay" or "dzeh-dzeh-dzeh". They also have a thinner, more drawn-out "eez-eez-eez" or "si-si-si" contact call. A short, sharp "zit" alarm call can also be heard. Hearing these calls is often the first and best clue to a Willow Tit's presence.

Conservation Status & Severe Declines

The Willow Tit is facing alarming population declines across much of its European range, particularly in Western Europe.

Current Status and Declines

While globally classified as "Least Concern" by IUCN due to its vast overall range, the Willow Tit is a species of high conservation concern in many individual countries. In the UK, for instance, it is on the Red List due to a catastrophic decline of over 90% since the 1970s, making it one of the UK's fastest declining resident birds. Similar declines have been noted in other Western European nations.

Threats

The reasons for these declines are complex and not fully understood, but likely involve a combination of factors:

• Habitat Loss and Degradation: Loss of damp, scrubby woodland and young successional habitats. Drainage of wet areas.
• Lack of Suitable Nesting Sites: Removal of dead and decaying trees (snags and stumps) due to 'tidying up' of woodlands and parks.
• Changes in Woodland Structure: Maturation of woodlands leading to loss of understorey, and increased shade reducing ground flora.
• Increased Predation: Higher populations of predators like Great Spotted Woodpeckers (which predate nests) may play a role in some areas.
• Reduced Food Availability: Possible declines in insect prey.
• Competition: From other tit species, although less clear.

Conservation Efforts

Conservation efforts focus on habitat management to create and maintain suitable damp woodland and scrub, retaining deadwood for nesting, and further research into the causes of decline. The RSPB (Royal Society for the Protection of Birds) has specific information on Willow Tit conservation: RSPB Willow Tit Conservation.

Interesting Facts About Willow Tits

• The Willow Tit is one of the few small passerines in Europe that regularly excavates its own nest cavity from scratch.
• Its English name likely refers to its preference for habitats with willow trees or its wood-boring nesting habits.
• Despite their declines, they can still be found in suitable habitat if one knows what to look and listen for.
• The distinct subspecies found in Britain and Ireland (Poecile montana kleinschmidti) is slightly darker than continental European forms.
• Their ability to remember the locations of hundreds of cached food items is remarkable.