Marsh Tits – Observations of a Species Under Threat

Marsh Tits in Woodcock Wood

Whenever we visit the wood we put up a bird feeder during our stay to see what takes an interest. We started this in 2018. Blue Tits, Great Tits and Nuthatches were the first to discover it and soon became regular visitors.

We first saw the pair of Marsh Tits in February 2019, and they were regular visitors throughout the spring and summer, and into the autumn.

Distinguishing Marsh Tits from Willow Tits

For a while during that first year, they posed a conundrum because Marsh Tits are almost identical in appearance to Willow Tits, and we had to research the difference to be certain of the ID. 

There are differences in appearance, but they are subtle for the non-expert, and even for the expert not always reliable ¹. A pale spot on the upper mandible of the Marsh Tit is a small but clear identifier, but is a challenge to see.

Behaviour is an important clue – the Collins Guide uses the term “fearless” for Marsh Tits. This is less to do with aggression, as with Nuthatches, and more to do with boldness. Our birds certainly exhibited this, as they seem to take little notice of our presence near the feeder.

There are two unambiguous distinctions: their call and their nest building behaviour, neither of which are necessarily helpful for identification during a brief observation of a bird. 

The Marsh Tit’s main call is a sneeze-like itishoo, while the Willow Tit’s is a harsh chaychay sound. 

The Marsh Tit will chip away at the entrance of a prospective hole to enlarge or reshape it for a nesting cavity. The Willow Tit will excavate the entire hole, which seems surprising given its relatively small beak. It certainly doesn’t have the chisel-like beak of the Woodpecker family. Other than the woodpecker, it is the only British bird to excavate its own hole: https://www.youtube.com/watch?v=pUPycyGb4Hs

Population and Distribution of the Marsh and Willow Tit

Both species are widely distributed across Europe and Asia. Globally they are still classified as having a stable population, but in the UK their populations are decreasing dramatically, and both are Red Listed.

In fact the Willow Tit is the UK’s second fastest declining species after the Turtle Dove, with a decrease of 98% of its population since the 1970s. It is now regarded as extinct in most of the South and South East of England ². This point alone eliminates any confusion between the two species, for us in the South East, but of course there are still areas where their distributions overlap.

Marsh Tits are still widespread across the Midlands and the south of England, but occur less frequently towards the north. They are more or less absent in Scotland and Ireland. 

Overall their numbers are in sharp decline. In the words of Broughton and Hinsley: 

“The plight of the Willow Tit shows how bad things could become for its closest relative (the Marsh Tit). Thirty years ago the Willow Tit was just as widespread as the Marsh Tit, and almost as abundant, but it is now … under serious threat. With no sign of recovery , the Marsh Tit may follow suit and be lost from parts of England and Wales and from Scotland completely.” ³

Habitat and Behaviour

Marsh Tits favour mature woodland with a dense understory. They pair for life, and maintain large territories of about 12 acres (5 hectares) which they defend during the breeding season. At other times they may forage with mixed groups of birds including Marsh Tits from adjoining territories.

The individual pairs develop a detailed knowledge of their territory, and often lead other species to available food sources. We’ve observed them being the first and sometimes only birds to come to the feeder, particularly when it’s been available for only a short time.

They also seem to forage more readily on the ground, far more so than Great Tits and Blue Tits. 

Why the Steady Decline?

It’s likely to be a combination of factors. Habitat loss, an increase in the numbers of key predators, particularly the Great Spotted Woodpecker; or a loss of connectivity between occupied territories and potential territories are almost certainly relevant factors. 

However, Broughton and colleagues, in a recent article ⁴, argue that while habitat loss is a very important factor in the decline of the Willow Tit in the UK, but recent developments in woodland restoration in the UK actually favour the Marsh Tit. Then, why are we seeing such a marked decline in their numbers?

Broughton et al’s main proposition is that the huge increase in garden bird feeders has produced a large increase in the Blue and Great Tit populations. These birds are not tied to territories in the same way as Marsh Tits, and are able to move into and out of woodlands as nesting and foraging require. They are out competing the sedentary and less versatile Marsh Tit. 

The adult Marsh Tit, as we have observed, is a feisty bird, and not prone to being put off food sources. But juvenile Marsh Tits suffer in the competition. 

Broughton et al also argue that the growth in garden bird feeding has also benefited the population of the Greater Spotted Woodpecker, a key predator of the tit species. (The decline in the Common Starling population has also benefited the woodpecker – see: https://woodcockwood.com/greater-spotted-and-lesser-spotted-woodpeckers.)

Although Broughton et al recognise that there is no direct evidence that the burgeoning Blue and Great Tit populations are a cause of the decline in the Marsh Tit, they advise that as a precautionary measure we should avoid providing food specific to the tit family (sunflower seed etc) and nest boxes in areas close to known Marsh Tit territories – certainly a point worth considering.

Difficulties in Observation

Our woodland is part of a 60 acre (25 hectare) wood in a well wooded area on the Kent / Sussex border. The wood comprises conifer stands within unmanaged chestnut coppice and occasional semi-mature oaks. Sections of our wood are heavily over grown with dense young birch. This represents ideal Marsh Tit territory. 

Although we frequently saw the pair throughout 2019, they disappeared during the spring and summer in 2020. Towards the end of the year they, or a new pair, arrived on the scene and have been showing themselves at the feeder since then.

We have assumed that they nest, but have been unable to identify where, partly because they favour the dense growth of young birch, and it isn’t easy to follow them. We haven’t even seen them caching food. 

Nest Boxes

The literature says they don’t readily take to nest boxes, and if they do, they will only uses boxes with a small hole and floor area. The recommended design is 10cm X 10cm floor area, with 2.6 cm hole, fixed at chest height in dense clumps of birch saplings – see report A Nest Box Trial for Marsh Tits: https://www.tandfonline.com/doi/full/10.1080/03078698.2014.995414. 

In early 2020 we provided two double boxes of recommended dimensions in what we thought to be suitable locations. One of the four holes was used by Blue Tits in both 2020 and 2021. They are still in place for this year.

Notes:

¹ If you wish to follow up this identification conundrum in more detail try the British Trust for Ornithology’s site: https://www.bto.org/develop-your-skills/bird-identificatio n/videos/telling-apart-marsh-and-willow-tits.

² Back from the Brink Project – www.naturebftb.co.uk – a partnership of 7 conservation charities including the RSPB. The Willow Tit is one of their target species.

³ Richard K. Broughton and Shelley A. Hinsley “The Ecology and Conservation of the Marsh Tit in Britain” British Birds, January 2015, Vol 108, 12-29

⁴ Richard Broughton, Jack Shutt, Alexander Lees “Rethinking Bird Feeding: are we putting extra pressure on some struggling woodland birds?” British Birds, January 2022, Vol. 115, 1-60.

See also article on the use of bait in bird photography: https://woodcockwood.com/bait-in-bird-photography-and-conservation-research/

Chris and Chris Saunders February 2022

For Site Index and Full List of Birds Discussed:

• https://woodcockwood.com/site-contents-and-index/