By Richard White
We live in a society that is increasingly data driven. It’s overwhelming how much information is out there and one of the major challenges is setting the right filters so we can see what we are looking for. A quick look at eBird data for Singapore at the time of writing (8 March 2025) shows that there are over 88,000 checklists. If there were an average of 12 records per checklist, this would mean there are a million records in this dataset.
Some of the over 88,000 checklists are accompanied by photographs that provide additional quality to the data reported. Are you able to find birds hiding in these pictures?
If we are looking for the answer to a question, how do we go about this? Fortunately, eBird data can be downloaded and analysed by those talented enough (not me). There are some more manual ways to check the information, but it takes time. While examining this valuable wealth of data, there’s an important caveat to bear in mind. It’s entirely based on the presence of birds, not on their absence.
When submitting an eBird checklist there is a specific box to check to state whether this is a complete checklist or not i.e. all species observed are recorded. But should a complete checklist include species that should have been seen but were not, such as a target species that was not found.
It’s easy to get silly about this – of course we’re not going to go out on a daily basis and record every species that we don’t see. But somewhere between the recording everything that we see and recording everything we don’t; I would argue that there is a valuable point about the value of a zero count.
Why would we care about a zero count? Primarily, those with a strong conservation interest will be looking to highlight scarce and declining species. Anyone chasing a year list is also acutely aware of what is missing or getting harder to find on an annual basis. I see it as one role of the Bird Society of Singapore to draw attention to trends in local bird populations, hence this article.
One thing that eBird data does allow for quickly and easily is to check when a species was last seen. To look at Singapore, the first wild species on this list is a Brown Booby from 1878. There’s then many other species that have not been recently recorded, not entirely comprised of vagrants but also including some former breeding species such as Moustached babbler and Crimson-winged woodpecker.
To look more recently, from 2015 onwards, here’s a quick run through of some of the species that have changed their status and may be considered going; or gone:
IUCN Least Concern
Until around 2021 this species was regularly recorded from ponds in the Punggol area. However, this species became locally extinct there. The species still occurs occasionally, and has been known to breed in the past. There are well founded rumours of a small population on a pond on the inaccessible Jurong Island. Otherwise, the most recent record was single seen on Pulau Ubin in January 2025.
Least concern
A small number of this species was regularly recorded at the Eco Lake in Singapore Botanic Gardens until December 2016. The birds were no doubt escapees from a local waterfowl collection. Since then there have been no further records and it seems unlikely that any genuine vagrants will occur.
IUCN Least Concern
Formerly a regular, if difficult to observe, resident of Kranji Marshes this species was last recorded in May 2018. The elevation of this location to a nature reserve in 2016 appears to have not benefited this species.
IUCN Least Concern
Formerly a regular at sites like Sungei Buloh this species was last recorded in August 2021 at Pulau Tekong, and the last “publicly available” bird was January 2019 on Ubin. The decline of this species is no doubt linked to the wider decline of shorebird populations within the East Asian Australasian Flyway and it seems likely that other shorebirds will share the same fate.
IUCN Least Concern
This species was regular at the summit of Bukit Timah summit in the past but recent sightings are scarcer, with the last on eBird from 10 June 2024. The species has been recorded occasionally since then at other locations in Singapore, such as a single at Chek Jawa in June 2024. As with Wandering whistling duck, this species is introduced to Singapore.
IUCN Least Concern
This species was formerly regular in the Central Catchment Nature Reserve, but has not been recorded there since October 2022. The species has been recorded occasionally since then at other locations in Singapore.
IUCN Near Threatened
Until 2017 this species was regularly recorded in the Central Catchment Nature Reserve. Since then, there have been occasional records from Pulau Ubin and most recently a single seen from Jelutong Tower in January 2025. This species may be slightly under-recorded due to the difficulty in separating it from the commoner Greater Green Leafbird, however there is no doubt that the species is less common than previously.
IUCN Least Concern
The continued presence of this species in Singapore seems tenuous and often suspect, with a sighting in December 2024 in the traditional Mount Faber area ending a barren period with very few records. Whether this population is genuinely wild or derived from a population of escapees is another question.
With the exception of Lesser Green Leafbird, all the species here are ranked as “Least Concern” by the International Union for the Conservation of Nature. As such, none would be seen as a conservation priority. The loss of species locally reflects ongoing habitat degradation and loss of biodiversity within Singapore that has been well documented and can undermine claims to be a “City in Nature”. Further, local declines frequently reflect bigger regional or global issues; such as habitat loss as lowland forest is cleared or the reduction of shorebird populations on the East Asian Australasian Flyway.
Associated with these observations are a number of questions. Can we be sure that none have been seen rather than simply no-one looking? In the case of a small country like Singapore, we can be reasonably happy that these birds are absent, but how long between a “last sighting” and a decision that they have been lost? How many other species are going the same way? What did I miss? Is anyone paying attention and who decides whether these declines or losses are of conservation concern and whether any mitigating action should be taken?
It’s my view that the Bird Society of Singapore should be actively seeking answers to these questions. This can be done by directing effort to record the presence (and absence) of species thought to be in decline. The availability of a platform like eBird to coordinate these efforts is valuable, but we have to be able to see what is not there as well as what is.
The two photographs at the start of the article, in fact, had no birds hiding in them. Days that lack birds are boring, but such days too provide us important data points.