The Marsh Tit – nesting, dispersal and conservation
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
Initially 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 easy1. A pale spot on the upper mandible of the Marsh Tit is a small but clear identifier. It is difficult to see in the field, but usually shows up in photographs and in close observation of the bird. The bill of the Willow Tit is an intense black. Richard Broughton undertook a systematic investigation of this, and found it an extremely reliable distinction2. His book also outlines the other physical differences.
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 exhibit this, as they seem to take little notice of our presence near the feeder.
The call is also an important means of distinguishing the two species. The Willow Tit’s main call is a harsh chaychay sound, and the Marsh Tit’s is an easily recognisable sneeze-like itishoo.
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
Marsh Tits
Habitat and Behaviour
Marsh Tits favour mature woodland with a dense understory. They pair for life, and maintain large territories of 5 or 6 acres or more 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.
The seeds of herbs, flowers and trees are their predominant food source, and they are particularly attracted to the oily sunflower seed from seed feeders.
They also seem to forage more readily on the ground, far more so than Great Tits and Blue Tits.
Marsh Tits are compulsive food cachers. Whenever they find a good food source they will eat their fill and then will be back and forth to collect and hide as much as possible. Food is cached in numerous crevices and holes close to the source for later recovery.
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 (see below).
However, Broughton and colleagues4 argue that while habitat loss is a very important factor in the decline of the Willow Tit in the UK, 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 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.
Nesting Behaviour, and Dispersal of Young Also Holds a Significant Clue to the Decline
Woodcock Wood, our woodland, is part of Goldwell Wood, 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.
Marsh Tits nest in small cavities and holes fairly close to the ground in secluded parts of the wood.
The literature says they don’t readily take to nest boxes, and if they do, they will only use 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.
Our pair obviously had a favoured nest site, but we were unable to find its location, and in early 2020 we provided two double boxes of recommended dimensions in what we thought to be suitable locations. Blue Tits used one of these in 2020 and 2021.
In 2022 and each year since, Marsh Tits have successfully raised a single brood in one of the boxes.
They typically lay about 10 eggs, and 8 or 9 young fledge e.g. in 2025 there were 11 eggs and 9 young fledged.
They nest about 10 days earlier than Blue Tits.
Dispersal of the Young
Marsh Tits are territorial, and breeding pairs defend their territories during the breeding season.
After the young fledge, they stay in the parent birds’ territory for only about 10 days before moving on. This seems to be an innate behaviour, with no apparent aggression shown by the adults.
The young birds move on quickly in order to find a territory of their own. The majority usually settle within 4 to 5 kms of their natal area.
They look for either an unoccupied woodland patch, or an existing territory with a single Marsh Tit of the opposite sex. This single bird may be a breeding adult that has lost its mate, or a newly arrived fledgling from another brood.
If a young bird cannot find a suiable territory, its chances of survival are small.
Once a bird is established in a territory, that bird becomes dominant. There is little competition from a new arrival, even if the new arrival is a bigger and stronger bird. Therefore, in finding territiories, time is of the essence. The earlier a bird is established the better, hence the rush to leave the natal area as soon as is possible.
The main restriction that young Marsh Tits face is their unwillingness to fly over open ground. They will only travel through woodland or follow dense hedge rows to access the new territory.
A population of Marsh Tits living in isolated woodland will soon die out, as there is no possibility of fresh blood in. This factor may be one of the main reasons for the steep decline in population over the last 30 years.
For Site Index and Full List of Birds Discussed:
https://woodcockwood.com/site-contents-and-index/
Notes:
- 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. ↩︎
- Richard Broughton has studied Marsh and Willow Tits for over 25 years, and has recently published a beautifully written and comprehensive study of the two species: “The Marsh Tit And The Willow Tit” 2025, Richard K Broughton, Published by T and AD Poyser. ↩︎
- 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 ↩︎
- 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. ↩︎