This page is dedicated to a nocturnal flight call project in Beijing in autumn 2021. The project is a collaboration between Birding Beijing and the Asian Infrastructure Investment Bank (AIIB).
We are recording every night – from dusk until dawn – from 25 August until 15 November 2021. The recording location is the roof of AIIB’s headquarters in Beijing.

The AIIB headquarters is situated in a 15-storey building immediately south of the Olympic Forest Park. This location is not close to any major roads and suffers very little from aircraft noise, so it’s the ideal place to conduct a recording project.
We purchased a Wildlife Acoustics Song Meter Mini (weatherproof and programmable), and set it up on the roof, programming it to record during the night (dusk to dawn) from 25 August until 15 November. The recorder is perfect for this project as the only maintenance needed is a change of batteries every two weeks or so. The 512GB memory card is capable of storing all the files for the whole period.

The objectives of the project are as follows:
- To gain an insight into the volume of birds flying over Beijing at night during autumn migration in order to engage the public about the extent of migration that happens over the city as its residents sleep
- As far as possible, to identify the species and establish their migration patterns
- If possible, establish links between weather patterns and the volume of nocturnal migration
It’s a time-consuming process to analyse the files but using the excellent free sound analysis software, “Audacity“, to produce spectograms in order to ‘visualise’ the files means it’s relatively easy to find the bird calls and skip through periods of silence. It is likely to be well into 2022 before all files are analysed but significant findings and updates, including mystery calls, will be posted here.
Huge thanks to the AIIB team, especially Sir Danny Alexander, Alberto Ninio and Li Zeyu, for their help and ongoing support for this project. Special thanks also to Geoff Carey for advice and assistance, including with identifications, to David Darrell-Lambert for advice about NocMig and for identifications, to Paul Holt and to members of the East Asian Bird Vocalisations WeChat Group and the NocMig WhatsApp group for ongoing help with identifications.
Header image: The AIIB Headquarters in Beijing.
Latest news:
31 January 2022
All files have now been analysed and logged. A total of 34,716 calls involving at least 55 species were logged between the period 25 August to 2 November. The graph below shows the volume of calls per night over the recording period.

More analysis will appear here in due course, including a list of species, their migration windows and some of the best recordings. Watch this space!
Working with Peking University, we are preparing a short public and media briefing that will take place at AIIB’s headquarters in the spring, with an accompanying paper to be written and submitted to a scientific journal.
We are advancing plans to record again in spring and autumn 2022 and to expand the recording locations across the city so that we can compare urban and rural locations.
19 December 2021
All files from 25 August to 30 September have now been fully analysed. During that period there were 6,013 ‘call events’ involving a total of 25,698 individual bird calls, with 33 species identified. The busiest file so far was between 0502 and 0602hrs on 29 September with 1,011 individual calls. More detail soon. Now the work begins to analyse the files from October and early November!
10 December 2021
Thanks to The Economist, and in particular their Beijing-based correspondent Ted Pflaker, for highlighting the Beijing nocturnal bird migration project on “The Intelligence” podcast, a summary of the key stories of the day. You can listen to the podcast here or by clicking the image below (total length 22 minutes with the Beijing project the last item at 17m30s.)
With a month of the sound files processed, the current total is 14,128 calls involving at least 30 species, with the most common being Olive-backed Pipit, Common Rosefinch, Night Heron and Eurasian Skylark.
9 December 2021
An unidentified waterbird, possibly Grey-tailed Tattler (Tringa brevipes 灰尾漂鹬 Huī wěi (piào) yù), from 0125 hrs on 19 September 2021. Two calls in the recording, the first a two-note call and the second a single note (see spectogram below). Closest match from Xeno-canto seems to be Grey-tailed Tattler. Thoughts welcome.
Download this file (.wav) Possible Grey-tailed Tattler
9 November 2021
A Brambling (Fringilla montifringilla 燕雀 Yànquè) from 26 October 2021 @ 0305 hrs.
Download this file (.wav) Brambling
28 October 2021
A good call of Pallas’s Bunting (Emberiza pallasi 苇鹀 Wěi wú) from 22 October 2021 at 0518 hrs.
Download this file (.wav): Pallas’s Bunting
26 October 2021
A nice series of six Siberian Accentor (Prunella montanella 棕眉山岩鹨 Zōng méishān shí liù) calls from 26 October 2021 at 0540 hrs.
Download this file (.wav): Siberian Accentor
And an unidentified call from 26 October 2021 at 0551 hrs.
Download this call (.wav): unidentified
17 October 2021
Three weeks of files have now been analysed and over 5,000 calls have been logged, the vast majority of which have been identified to species. Common Rosefinch (Carpodacus erythrinus 普通朱雀 Pǔtōng zhūquè), Olive-backed Pipit (Anthus hodgsoni 树鹨 Shù liù) and Eurasian Skylark (Alauda arvensis 云雀 Yúnquè) have dominated so far with a good selection of other species including Black-crowned Night Heron (Nycticorax nycticorax 夜鹭 Yè lù), Striated Heron (Butorides striata 绿鹭 Lǜ lù), Great Bittern (Botaurus stellaris 大麻鳽 Dà má jiān), Green Sandpiper (Tringa ochropus 白腰草鹬 Bái yāo cǎo yù), Common Sandpiper (Actitis hypoleucos 矶鹬 Jī yù), Wood Sandpiper (Tringa glareola 林鹬 Lín yù), Common Redshank (Tringa totanus 红脚鹬 Hóng jiǎo yù), Eurasian Curlew (Numenius arquata 白腰杓鹬 Bái yāo biāo yù), Forest Wagtail (Dendronanthus indicus 山鹡鸰 Shān jí líng), white-eye sp. (Zosterops sp., 绣眼鸟 xiù yǎn niǎo), Yellow-bellied Tit (Periparus venustulus 黄腹山雀 Huáng fù shānquè), and lots of thrushes and Muscicapa flycatchers (still to be identified to species). The sections below includes some typical calls of the more common species we are recording and a batch of currently unidentified calls, including .wav files and spectograms. Any suggestions about the identification of these calls are welcome.
Typical Calls
Green Sandpiper (Tringa ochropus 白腰草鹬 Bái yāo cǎo yù), 3 September 2021 at 0045 hrs.
Download this file (.wav): Green Sandpiper
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Black-crowned Night Heron (Nycticorax nycticorax 夜鹭 Yè lù), 6 September 2021 at 1853 hrs. Ninety seconds of Night Heron calls just after dusk.
Download this file (.wav): Night Heron
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Olive-backed Pipit (Anthus hodgsoni 树鹨 Shù liù), 6 September 2021 at 2305 hrs
Download this file (.wav): Olive-backed Pipit
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Common Rosefinch (Carpodacus erythrinus 普通朱雀 Pǔtōng zhūquè), 12 September 2021 at 0257 hrs
Download this file (.wav): Common Rosefinch
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Common Rosefinch (Carpodacus erythrinus 普通朱雀 Pǔtōng zhūquè), 30 September 2021 at 0421 hrs, with Olive-backed Pipit (Anthus hodgsoni 树鹨 Shù liù) at 7s.
Download this file (.wav): Common Rosefinch with Olive-backed Pipit
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White-eye sp., (Zosterops sp., 绣眼鸟 xiù yǎn niǎo), 30 September 2021 at 0524 hrs, with Olive-backed Pipit and bunting sp.
Download this file (.wav): White-eye sp.
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Eurasian Skylark (Alauda arvensis 云雀 Yúnquè), 1 October 2021 at 0221 hrs
Download this file (.wav): Eurasian Skylark
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Yellow-bellied Tit (Periparus venustulus 黄腹山雀 Huáng fù shānquè), 2 October 2021 at 0543 hrs
Download this file (.wav): Yellow-bellied Tit
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Unidentified Calls
Unidentified, 27 August 2021 at 0203 hrs. Single call between 3s and 3.5s.
Download this file (.wav): unidentified 27 August 2021 at 0203 hrs
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Unidentified, 28 August 2021 at 1930 hrs. Is this a bird?
Download this file (.wav): unidentified 28 August at 1930 hrs
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Unidentified, 30 August 2021 at 0135 hrs. Series of calls between 2s and 21s.
Download this file (.wav): 30 August 2021 at 0135 hrs
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Unidentified, 30 August 2021 at 0256 hrs. Possible cuckoo sp.?
Download this file (.wav): 30 August 2021 at 0256 hrs
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Unidentified, 30 August 2021 at 0423 hrs. Series of calls between 3s and 17s.
Download this file (.wav): 30 August 2021 at 0423 hrs
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Unidentified, 30 August 2021 at 2311 hrs. Two-note tit-like call at 3s.
Download this call (.wav): 30 August 2021 at 2311 hrs
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Unidentified, 2 September 2021 at 0017. Single call between 4s and 5s.
Download this file (.wav): 2 September 2021 at 0017 hrs
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Unidentified, 2 September 2021 at 0033. Chattering call between 3.5-4.5s. Possible Brown Shrike (Lanius cristatus 红尾伯劳 Hóng wěi bóláo)?
Download this call (.wav): 2 September 2021 at 0033
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Unidentified, 4 September 2021 at 1958 hrs. Heron or bittern sp.? Three calls at 4s, 11s and 20s. Identified as Striated Heron (Butorides striata 绿鹭 Lǜ lù) by Paul Holt on 17 October 2021.
Download this call (.wav): 4 September 2021 at 1958 hrs
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Unidentified, 5 September 2021 at 0200. Possible Little Grebe? (Tachybaptus ruficollis 小鸊鷉 Xiǎo pì tī).
Download this file (.wav): 5 September 2021 at 0200
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Unidentified, 5 September 2021 at 0402 hrs. Calls between 3s and 3.5s. Presumably a thrush sp.?
Download this call (.wav): 5 September 2021 at 0402 hrs
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Unidentified thrush sp., 7 September 2021 at 0156 hrs.
Download this call (.wav): 7 September 2021 at 0156 hrs
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Grey Heron (Ardea cinerea 苍鹭 Cāng lù) plus series of unidentified waterbird calls, 8 September 2021 at 0413 hrs. Waterbird identified as Long-billed Plover by Paul Holt on 17 October 2021.
Download this file (.wav): 8 September 2021 at 0413 hrs
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Unidentified (thrush sp.), 9 September 2021 at 0400 hrs.
Download this file (.wav): 9 September 2021 at 0400 hrs
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Unidentified, 9 September 2021 at 0438. Muscicapa flycatcher? Call at 4.5s.
Download this call (.wav): 9 September 2021 at 0438
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Unidentified, 11 September 2021 at 0000 hrs. Richard’s Pipit (Anthus richardi 理氏鹨 Lǐ shì liù) or Blyth’s Pipit (Anthus godlewskii 布氏鹨 Bù shì liù)? Calls between 4s and 5s. Identified as Richard’s Pipit (Anthus richardi 理氏鹨 Lǐ shì liù) by Paul Holt on 17 October 2021.
Download this file (.wav): 11 September 2021 at 0000 hrs
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Unidentified, 11 September 2021 at 0007 hrs. Call at 4.5-5s.
Download this call (.wav): 11 September 2021 at 0007 hrs
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Probable Rosy Pipit (Anthus roseatus 粉红胸鹨 Fěnhóng xiōng liù), 11 September 2021 at 0012 hrs
Download this file (.wav): 11 September 2021 at 0012 hrs
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Unidentified, 11 September 2021 at 0132 hrs. Call at 3.5s.
Download this file (.wav): 11 September 2021 at 0132
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Unidentified, 11 September 2021 at 0123 hrs. Call at 5s. Possibly a waterbird (Coot?).
Download this file (.wav): 11 September 2021 at 0123 hrs
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Unidentified, 11 September 2021 at 0150 hrs. Three-note call between 5s and 6s.
Download this file (.wav): 11 September 2021 at 0150 hrs
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Unidentified, 12 September 2021 at 0130 hrs.
Download this file (.wav): 12 September 2021 at 0130 hrs
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Unidentified, 14 September 2021 at 0013 hrs. Single call between 3.5s and 4s.
Download this file (.wav): 14 September 2021 at 0013 hrs
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Unidentified, 14 September 2021 at 0347. Eight calls of a bunting sp. between 5s and 14s. One Common Rosefinch (Carpodacus erythrinus 普通朱雀 Pǔtōng zhūquè) between 7s and 8s and one two-note unidentified call between 6s and 7s.
Download this call (.wav): 14 September 2021 at 0347 hrs
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Unidentified, 28 September 2021 at 0245 hrs. We are recording several of these distinctive-looking calls, usually singly, in late September and early October.
Download this file (.wav): 28 September 2021 at 0245 hrs
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Unidentified thrush sp., 28 September 2021 at 0304 hrs. Call at 5s.
Download this file (.wav): 28 September 2021 at 0304 hrs
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Possible Coot (Fulica atra 骨顶鸡 Gǔ dǐng jī), 29 September 2021 at 0011 hrs. Call between 4s and 5s.
Download this file (.wav): 29 September 2021 at 0011 hrs
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Unidentified, 29 September 2021 at 0226 hrs. Call between 5s and 6s.
Download this file (.wav): 29 September 2021 at 0226 hrs
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Unidentified, 29 September 2021 at 0551 hrs. Calls at 5s and between 16s and 17s.
Download this file (.wav): 29 September 2021 at 0551 hrs
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Unidentified three calls, 29 September 2021 at 0521 hrs (last two only shown on spectogram below, between 7s and 8s and between 14s and 15s). Identified as Eurasian Skylark on 17 October 2021 by Paul Holt.
Download this file (.wav): 29 September 2021 at 0521 hrs
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Unidentified, 29 September 2021 at 0502 hrs. Call at 3s.
Download this file (.wav): 29 September 2021 at 0502 hrs
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Unidentified, 30 September 2021 at 0508 hrs. Two-note call at 4s and four-five note call at 14s.
Download this file (.wav): 30 September 2021 at 0508 hrs
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Unidentified, 1 October 2021 at 0207 hrs. Downward inflected call at 5s.
Download this call (.wav): 1 October 2021 at 0207 hrs
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Unidentified, 1 October 2021 at 0244 hrs. Scratchy calls between 4.5s and 5s.
Download this file (.wav): 1 October 2021 at 0244 hrs
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Unidentified thrush sp., 1 October 2021 at 0400 hrs. Single call at 4.5s.
Download this call (.wav): 1 October 2021 at 0400 hrs
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Unidentified, 1 October at 0508 hrs. Possibly just a slightly odd Olive-backed Pipit?
Download this call (.wav): 1 October 2021 at 0508 hrs
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Unidentified, 3 October 2021 at 0420 hrs. Three calls at 4s, 9s and 14s.
Download this file (.wav): 3 October 2021 at 0420 hrs
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Unidentified (waterbird?), 2 October 2021 at 0423 hrs. One call at 4.5s.
Download this call (.wav): 2 October 2021 at 0423 hrs
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Unidentified, 2 October 2021 at 0412 hrs. Four-note downward-inflected call between 4s and 5s.
Download this file (.wav): 2 October 2021 at 0412 hrs
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Unidentified, 2 October 2021 at 0546 hrs. Three-note call just after 4s. Calls between 0 and 0.5s, at 1.5s and 2-2.5s are Yellow-bellied Tit (Periparus venustulus 黄腹山雀 Huáng fù shānquè). Three-note call also identified as Yellow-bellied Tit on 17 October 2021 by Paul Holt.
Download this file (.wav): 2 October 2021 at 0546 hrs
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