Irish Name: Caipín dubh
Scientific name: Sylvia atricapilla
Bird Family: Warblers
Conservation status


Scarce summer visitor to woodlands in the midlands and northern Ireland from April to September. Also a scarce passage migrant mainly in spring and autumn to headlands on southern and western coasts. Although Irish-breeding Blackcaps still migrate southwards in the autumn, some Blackcaps from the population that breeds in Central Europe migrate to Ireland to spend the winter. One of Ireland's top 20 most widespread garden birds


About the same size as a Robin. Adult male Blackcaps have a distinct black cap, covering most of the head. The rest of the body is a rather grey-colour, while the vent is white. Adult female Blackcaps have pale brown cap, similar in extent to that of the male. The rest of the body is grey-brown, not as dark as the male.


A hard "teck", frequently given in a long series. Also infrequently gives a "yu-teck" call. The song is one of the most beautiful songs of all Irish songbirds. It is a rich, melodic series of notes ending in an ecstatic series of flute-like notes.


Feeds mainly on insects and other invertebrates during the summer. In winter, takes berries (Ivy, Rowan), as well as scraps from bird tables. Will use peanut feeders.


Widespread in lowlands throughout Ireland. Breeds in dense decidous woodlands and in mature hedgerows.


The majority of the Irish population migrate south to winter in Iberia and North Africa. There is a small wintering population, mainly in the east and south of Ireland. Recoveries of ringed Blackcaps have shown that the majority of these wintering birds originate from Central Europe.

Monitored by

Countryside Bird Survey and Garden Bird Survey

Blog posts about this bird

Birds of Prey

Irish Garden Birds 2020 - How much do your garden birds weigh?

There's still time to get started with the Irish Garden Bird Survey!  It's the biggest and longest-running survey of it's kind in Ireland. We need as many people as possible all over the country to take part this winter. Taking part couldn't be easier - See here for details on how to participate this winter . See below for information on how much your garden birds weigh, and why feeding them at this time of year is so important! 


The Irish Garden Bird Survey is kindly sponsored by Ballymaloe. Click below to learn about taking part this winter.

  The birds in your garden are much more worried about putting on weight this Christmas than you are! If you have a small body, your surface-to-mass ratio is much higher, which means there's more of a surface area for your body heat to escape from - i.e. you can lose heat very quickly. Heat is energy, and if you’re losing heat and burning off more body fuel than you put on each day then you’re in trouble! This is why feeding your garden birds is so worthwhile – not only are you giving them food high in calories, fat and protein, but you’re providing a predictable source of food so they don’t have to waste energy every day traversing the hedgerows of the countryside in search of any morsels that might keep them going. The winter days are short and the nights are long and cold, so anything that saves the birds energy is a gamechanger!   To really hammer home the point it’s worth thinking about just how little our garden birds actually weigh. We know this through bird ringing. Trained and licensed scientists and ornithologists, in a largely voluntary capacity, catch birds and fit them with a small metal ring to get an idea of how many individuals are in an area, how long they live, how far they travel and a whole host of other data which is pooled together to help us learn about some of the intricate details of the lives of our common and rare bird species. One of the standard bits of information recorded during ringing is the weight of the bird. People occasionally email BirdWatch Ireland saying they saw a ‘big Blackbird’ or a ‘small Starling’, but in reality the variation between individuals of the same species is generally quite small (except where males and females are quite different e.g. corvids, pigeons,  birds of prey). See below to get an idea of how much your garden birds weigh, and how much of a difference a few grams of peanuts, seeds or fatballs make to their attempt to survive the winter! And remember, if you're buying bird food, feeders, nestboxes and other bird-related gifts this winter then check out the BirdWatch Ireland Shop here - by buying from us you're also helping to support our conservation work!     Traditionally, one might compare the weight of a small bird to that of a coin or a known amount of coins but given the likelihood that your wallet or purse has more plastic cards than coins in it, lets go with that. So, the average bank or supermarket clubcard weighs 5g – keep that in mind!  

Less than 10 grams (two bank cards)

The smallest bird in Ireland is the Goldcrest – they weigh a mere 6g on average but can range from 4.7g (i.e. less than your bank card!) to 6.1g. Not far behind them, with average weights of 9-10g are Long-tailed Tit, Coal Tit, Treecreeper and Wren. These species will be the most active in your garden over the winter because the days are so short that they literally need to be feeding non-stop throughout the day to maintain their weight and survive the night! Wrens and Long-tailed Tits, amongst others, are known to communally roost during the winter – that is, they find some sheltered location and squeeze in together for the night in an effort to share body heat! In the case of Long-tailed Tits, because they’re all closely related they will take turns in the middle (i.e. warmest part) of the group before moving to the outside to give someone else a turn. For other species, where a roost will comprise of a number of unrelated individuals, they’re less generous, so you don’t want to be the last one in and stuck on the outside of the group!  

10-20g (two to four bank cards)

Some individual Blue Tits and Lesser Redpolls might come in at under 10g, but generally they average around 11g and can range up to 12.5g on a good day! Siskins are only slightly bigger at 13g, and then you have Goldfinch (17g), Great Tit (18g) and Robin (19g). Robins play it smart by staying territorial in the winter, and even the females will guard a territory – sometimes one where there’s suitable food but a lack of nesting space so it wouldn’t have been a core territory during the summer. By identifying somewhere with a suitable food source and aggressively guarding it, they save themselves a lot of energy and trouble having to range far and wide in search of food. Goldfinches do the opposite by flocking, but the more eyes in a flock the more likely you are to find food.

20-30g (four to 6 bank cards, or 3 or 4 € coins)

Despite looking much chunkier and heavier, Bullfinches weigh the same on average as the slimline Pied Wagtail (both 21g), and our wintering Blackcaps are the same. Chaffinch weigh in at 24g on average, and it won’t surprise you that House Sparrow (27g) and Greenfinch (28g) are at the top end of the scale when it comes to ‘small’ garden birds. Still, as heavy as they might be, you’re still talking a few bank cards, or four €1 coins! When you think about the battle for survival that these birds face day in day out, it’s amazing that something so small and slight can achieve so much! Don't forget, in the case of the Chaffinch some of the birds in your garden will have migrated from as far away as Scandinavia, in the hope that their chances of finding food and surviving the winter are better here, even taking into account the pressures of migration. Tipping the Scales Of course, there are some much bigger species that use Irish gardens. Despite all looking roughly the same size, there’s a lot of variation in the Thrush family. Redwings, which migrate here from Iceland and Scandinavia each winter weigh around 63g, our resident (and some migratory..) Song Thrushes range from 64-90g but usually come in around 83g, Blackbirds and Fieldfares both average around 100g and Mistle Thrush is the real heavyweight of the family at 130g.   Once you start looking at bigger birds, there tend to be more of a difference between the sexes, with males generally bigger than females for the crows and pigeons. Amongst the crow species, Jays weigh the least (168g), followed by Magpies and Jackdaws (220g, 230g), then Rooks (450g) and Hooded Crow (510g). In the case of Magpies, males are around 40g heavier than females and for Rooks there’s a 60g difference, with the others showing similar discrepancies. For the pigeons, Collared Doves (205g) weigh around half as much as Woodpigeons (507g). Imagine being a 10g Coal Tit, plucking spilled seeds from under a bird feeder when a Woodpigeon more than 50 times your size lands beside you!
Collared Doves look only a bit smaller than Woodpigeons, but actually Woodpigeons weigh twice as much!
  Lastly there’s the exception to the rule of sexes. Amongst many birds of prey the female is actually bigger than the male, and it’s the same for Sparrowhawks. Females weigh on average 266g (range 186-345g), while males are a third smaller at 151g (range 131-180g). Such a big discrepancy between such specialist birds means that male and female Sparrowhawks will actually target very different-sized prey to each other.   male-sparrowhawk-perching-on-mossy-rock
Male Sparrowhawks are a third smaller than females.
  When you realise just how small most of our garden birds are, you can really appreciate the importance of a reliable food source for them, particularly during the winter! Remember, BirdWatch Ireland needs your support now more than ever, and our annual membership makes for a great christmas gift that will keep on giving throughout the year! See here for full details.  

The Irish Garden Bird Survey is running right now and taking part couldn't be easier! Click here for full details about the survey as well as as advice on caring for your birds through the winter.

This winter we're running a series of blogs like this one, filled with facts and figures about your favourite garden birds, click here for more.

We are hugely grateful to Ballymaloe  for their sponsorship and support of the Irish Garden Bird Survey. 


Click below to download your count form for this year's Irish Garden Bird Survey.

Garden Birds

Irish Garden Birds get a spring in their step in February!

We're now into the home stretch of this winters Irish Garden Bird Survey, and this time of year tends to bring a lot of changes to the bird communities in Irish gardens! When the Irish Garden Bird Survey starts each December, there's often a good bit of food available to most species in the wider countryside - seeds on mature broadleaf trees, berries and fruits in hedgerows, and depending on how cold the weather has been there might even be a good supply of invertebrates around too. Couple that with the fact that our migrant thrush and finch species are still arriving into Ireland in December, and it means that the diversity and number of birds in your garden can be quite limited up until around Christmas. After that though, things start to change! That food in the wider countryside gets depleted, and birds are becoming more desperate for other sources of food. Day length is at its shortest at this time of year too, meaning less time for birds to find food and longer, colder nights for our tiny feathered friends to try and survive through. This period of the year has been shown to be hugely important to the survival and population numbers of farmland birds and is known as the 'hungry gap'. So its no surprise that this is the time of year when numbers of your favourite garden birds start to increase! See below for some information on species who will be making their presence felt in gardens across Ireland in the coming weeks, as shown over the 30 years of the Irish Garden Bird Survey to date! We wouldn't have this information if it wasn't for people like you taking part in the survey each year - so make sure to keep going for the final weeks of the survey so that we can build up an accurate picture of how Irish garden birds fared in winter 2019/20!


goldfinch IGBS graph

Goldfinch were only seen in around a third of Irish gardens 20 years ago, but their numbers have continued to increase since that time and now they're regularly seen in 80% of gardens each winter. They're seen in most gardens right throughout the Irish Garden Bird Survey, but the graph here shows their numbers in gardens increases significantly as the winter goes on! We often get people telling us that between sunflower hearts and nyjer seed, their local Goldfinches are eating them out of house and home - but who could be angry with a bird as beautiful and 'charming' as that?!

Read more about Goldfinches here.



Siskins are a small species of finch, with a small pointed bill adapted for feeding on very fine seeds, not unlike the Goldfinch. Like the Goldfinch too, they are a species that's very fond of nyjer seed, though they will readily take to peanut and sunflower seed feeders too. They are seen in barely any gardens in December, increasing a bit in January, but by the start of February much of the natural food they rely upon (seeds on trees like Alder and Sitka Spruce) are gone and your garden feeders provide the ideal substitute! Despite their slow start to the winter, they can occur in over 40% of gardens by the end of February each winter. Many of these birds will have come here for the winter from Scotland and Scandinavia, so they desperately need to refuel before migrating back in March and April!

Read more about Siskins here.



Lesser Redpoll

Another small finch, closely related to the Siskin, again with a fine bill and a similar excuse for being absent from gardens until after christmas, with numbers building into February and beyond! The red isn't always obvious on these birds, particularly on the females, and so some people can confuse them with other finch species including Twite (never come to gardens) or Linnets (much bigger!). If you have Goldfinches in your garden, chances are you have a good set up for attracting Redpolls too and they often come to nyjer, sunflower hearts and peanuts too!

Read more about Lesser Redpolls here.



The Blackcap is a warbler species, and like the other warblers we have in Ireland, those that breed here leave and migrate south for the winter. While our Irish-breeding Blackcaps are in Iberia and northern Africa during our winter months, Blackcaps from central Europe (same species, but a different population!) come to Ireland for the winter! This migratory route is thought to have developed in part due to the availability of food in Irish gardens, with a warming climate also likely to be playing a part. Numbers in gardens are low in December when there are still berries and fruits in the wider countryside to feed on, but by the end of February there'll be around three times as many Blackcaps in Irish gardens as there was when the Irish Garden Bird Survey started in December. They'll eat peanuts and fatballs in your garden, but also enjoy apples when cut in half and placed in a tree or on a bird table! Keep an eye out for brown-capped females too!

Read more about Blackcaps here.


And the rest...

The above are species that show a consistently strong trend, year after year, of increasing numbers from early December when the Irish Garden Bird Survey starts, to the end of February when the survey finishes. They're not the only species that show this trend though. Great Spotted Woodpeckers show a similar trend, though the effect isn't as strong as they still only appear in a small number of gardens in Ireland so far. For other species including Blackbird, Song Thrush, Redwing and Fieldfare, their occurrence in gardens is very weather dependent an you might see a big influx if we get snow or heavy frost in the coming weeks. The Pheasant hunting season is over for another year now too, so this may mean a wandering Pheasant might turn in your garden yet - taking advantage of any seed spilled beneath your feeders. If we get a mild February, you might start to see some territorial behaviour and birds leaving your garden as they start thinking about finding somewhere to nest.   Don't forget that now is the perfect time to put up a nestbox in your garden! We've got a wide selection of nestboxes available in our shop, and by buying from us you're also helping support or vital conservation work!

See our selection of nestboxes here.


The Irish Garden Bird Survey is BirdWatch Ireland's longest-running survey and is vital in tracking the fortunes of Ireland's garden bird species through the harsh winter months.

For more details about the survey click here.

The survey is sponsored by the Ballymaloe Group.


Similar Species

Garden Warbler

Irish Name:
Ceolaire garraí
Scientific name:
Sylvia borin
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Willow Warbler

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Irish Name:
Scientific name:
Phylloscopus collybita
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Lesser Whitethroat

Irish Name:
Gilphíb bheag
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