Science blog

Exploring science at the British Library

3 posts from August 2023

23 August 2023

50 years on: Information Retrieval and the British Library

The logo of BLAISE, showing BLAISE in angular letters in white on blue, with the full title "British Library Automated Information Service" and the original "open book" British Library logo
The fiftieth anniversary of the foundation of the British Library is an opportunity to look back at the leading role the Library and its parent bodies played in introducing computerised information retrieval for science and medicine to the UK. Between 1965 and 1975 experiments in searching databases of medical research were carried out in partnership with the US National Library of Medicine (NLM)  together with computer scientists and medical users in the UK. Following the success of these experiments the Library launched BLAISE (British Library Automated Information Service)  as a national public service in 1977.

The NLM began publishing Index Medicus, an index of medical journal articles, in 1879. In 1960 printing was computerised and the machine readable data on tape became available for information retrieval. A publicly available US service, MEDLARS (Medical Literature Analysis and Retrieval System) opened in 1963 with MEDLINE  (MEDLARS online) going live in 1971. [1]

 In 1965 the NLM agreed with the National Lending Library for Science and Technology [2] to supply tapes in exchange for MEDLARS records of UK medical literature. With these tapes in hand the Office of Science and Technology Information [3]  funded Newcastle University to develop a retrieval package based on NLM’s IBM software to run on the university’s English Electric computer. Subsequent projects in 1973-74 tested the online environment and current awareness services with medical researchers and librarians in Leeds and Manchester over an online telephone link. [4]

The next step in service delivery was to establish online access to the NLM. University College London had set up a link to the US through ARPANET, the early version of the internet [5], and in 1973 British Library Research & Development [3] along with other public bodies, joined this network. This programme was historically significant as the first international communication over the internet. Project STEIN (Short Term Experimental Information Network) involved sixteen centres (e.g. the Royal Post-Graduate Medical School) each with its own terminal and trained intermediary.  The number of users (362) and searches (1217) was substantial and the study confirmed the need for intermediaries who were experienced in using the system and formulating searches. The clinicians and researchers who accompanied each session evaluated the results and gave feedback. Despite difficulties with telecoms, satisfaction was high as searches delivered articles that were new together with articles that were familiar to the users, thus increasing their confidence in the search. [6]

These encouraging results led the Library in 1977 to launch BLAISE, a fully supported public service providing Medline and databases for toxicology and cancer. Tapes were delivered monthly from Washington by diplomatic bag to a computer bureau in Harlow to run on an IBM 370 machine with NLM’s ELHILL retrieval software. Mounting tested software on an established bureau service meant that BLAISE went live within a year. Users benefited from the dedicated BLAISE PSS (Packet Switched Service) network and a support team that provided training, documentation and a help desk, alongside document supply from the British Library Lending Division at Boston Spa.[7] At first researchers and clinicians used Medline for checking references or keeping up to date but it has since become an essential tool for the evidence based medicine community to generate systematic reviews and contribute to the Cochrane Library.[8] From 1977 the Library was the sole provider of NLM databases in the UK but in a political decision in 1982 NLM, as a federal agency, was required to release its products to US online providers. With the ensuing competition BLAISE was no longer able to support a UK based service and it was relaunched as BLAISE-LINK, a UK portal for online access to NLM. Within a few years customers moved over to commercial online hosts and BLAISE-LINK closed. 

Today, the Library continues online healthcare with the publication of AMED (Allied and Complementary Medicine Database). This database supplements the coverage of Medline in areas such as alternative medicine, palliative care and rehabilitation. [9]

We have come a long way in fifty years.  In 1973 searching involved expensive telecoms and computer access, clumsy equipment  (who now remembers audio-acoustic couplers?) minimal records, complex Boolean search strings and the need for skilled medical librarians to navigate all these obstacles. Now, there is free access to the internet and PubMed, open access full text and sophisticated relevance searching empowering every user. Information has exploded:  in 1976, Medline and its associated files had 3.5 million records, by 2022, PubMed had 35 million. [10] 

References [BL shelfmark]

All URLs accessed on 7 July 2023.

[1] MEDLINE History. https://www.nlm.nih.gov/medline/medline_history.html

[2] The National Lending Library for Science and Technology (NLLST) was the predecessor of the British Library Lending Division and later, the Document Supply Centre. The service is currently available as British Library On Demand.

Barr, D. P. The National Lending Library for Science and Technology. Postgraduate Medical Journal42.493 (1966): 695. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2466097/pdf/postmedj00407-0003.pdf

[3] The Office of Science and Technology Information (OSTI) was the predecessor of British Library Research & Development which promoted and funded R&D by the UK library and information community until its merger with the Library and Information Commission in 1999.

Baxter, P. "The role of the British Library R&D department in supporting library and information research in the United Kingdom." Journal of the American Society for Information Science 36.4 (1985): 276. https://www.proquest.com/openview/77a69cbd42dd0412f39b217892f95ac2/1?pq-origsite=gscholar&cbl=1818555 

[4] Barraclough, E. Information Retrieval, its origins in Newcastle. http://history.cs.ncl.ac.uk/anniversaries/40th/webbook/infoRetrieval/index.html

Harley, A. J., and Elizabeth D. Barraclough. MEDLARS information retrieval in Britain. Postgraduate medical journal 42.484 (1966): 69. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2465839/pdf/postmedj00398-0003.pdf

[5] Kirstein, P. T. "Early experiences with the Arpanet and Internet in the United Kingdom." IEEE Annals of the History of Computing 21.1 (1999): 38-44. https://citeseerx.ist.psu.edu/doc/10.1.1.112.8527

Computer History – Internet history of the 1970s.  https://www.computerhistory.org/internethistory/1970s/

[6]  Holmes, P. A description of the British Library’s short-term experimental information network project. pp 231-237 - 1st International On-line Information Meeting, London 13-15 December 1977 / organised by On-line Review, the international journal of on-line information systems. (1977). Oxford ; New York: Learned Information. [available in the British Library at shelfmark 2719.x.4085 ]

Holmes, P. (1978). On-line information retrieval: An introduction and guide to the British Library's short-term experimental information network project / P.L. Holmes. Vol.2, Experimental use of medical information services. (Research and development reports (British Library) ; no.5397). London: British Library Research and Development Department. [available in the British Library at shelfmark 2113.560000F BLRDR 5397 ]

Trials were also made with other scientific and engineering databases on the Lockheed Dialog system.

(7) Holmes, P. L. The British Library Automated Information Service (BLAISE). Online Review 3.3 (1979): 265-274. https://www.emerald.com/insight/content/doi/10.1108/eb024003/full/html       

BLAISE also provided bibliographic databases for the British National Bibliography and the Library of Congress, finally closing in 2002.

[8] McKibbon, K. A. Evidence-based practice. Bulletin of the medical library association 86.3 (1998): 396. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC226388/pdf/mlab00092-0108.pdf

Cochrane Library. https://www.cochranelibrary.com/about/about-cochrane-reviews

[9] Allied and Complementary Medicine Database (AMED) https://www.ebsco.com/products/research-databases/allied-and-complementary-medicine-database-amed

[10] Miles, W. (1982). A history of the National Library of Medicine : The nation's treasury of medical knowledge. (NIH publication ; no.82-1904). Bethesda, Md.: U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health, National Library of Medicine. [p.386 -3.5 m records, 1976] https://collections.nlm.nih.gov/bookviewer?PID=nlm:nlmuid-8218545-bk

PubMed Milestone - 35 Millionth Journal Citation Added. https://www.nlm.nih.gov/pubs/techbull/nd22/brief/nd22_pubmed_milestone.html

Further reading

Bourne, C., & Hahn, Trudi Bellardo. (2003). A history of online information services, 1963-1976, Cambridge, Mass. ; London: MIT. [Available in the British Library on open shelf: Humanities 2 Reading Room HUR 025.04]

Written by Richard Wakeford (Science Reference Specialist, Retired). Richard was a member of the BLAISE support team, 1981-1984.

15 August 2023

Wild British Library: Experiences of nature: goldfinch, pigeon and magpie

For us and for nature, facts are not enough. We need stories too.


Facts tell us something. We need facts, yes, but we need more. To understand facts, and for them to help us act, we need to connect with them in a way that is meaningful to us. Sharing our experiences of nature, especially in the form of stories, is one way of making connections, as Andrea Deri mentioned in her recent post. There, she described how naturalists over centuries have told us of their experiences of nature as well as their methodical observations. Although not a naturalist myself, I believe in the power of sharing stories. Here are two memorable experiences I have had at the Library.


A Charm of Goldfinches
Goldfinch: Carduelis carduelis

A goldfinch is seen perched on a twig in close up
Photograph courtesy of Greg Smith. Taken 2 Jan 2021, Alexandra Palace, London.

In the grey white days of one winter I frequently sat quietly in the staff lounge reading and looking out towards the Crick Institute. An occasional pigeon would attract my attention as it sped past. One day stands out in my mind, as I saw a flash of colour as well as movement. For a brief, beautiful moment, six goldfinches grazed on the grey, grassy mounds outside the window before taking to the air for some other, unimagined place.


The Pigeon and the Magpie
(Columba livia domestica and Pica pica)

A magpie is seen in close up perched on a rock
Photograph courtesy of Greg Smith. Taken 16 Oct 2022 at Alexandra Palace, London.

As I remember it now, it was a late winter’s day with just enough warmth and blue sky to raise my anticipation of spring. I was sitting on the piazza in the pale, promising sunlight when I turned my head briskly at a sudden movement sensed out of the corner of my eye. Up on the ornamental green bars at the corner of the Knowledge Centre, a pigeon was struggling to escape, one of its small feet apparently trapped. I winced after each desperate flutter, picturing its body hanging by a tendon in its tiny foot, imagining its pain. As I stared, I became aware of others around me who had also been captivated by the drama high above the ground. We released a collective groan as the drama darkened.
As we stared at the small body, hanging for longer and longer moments between flutters, a flash of black and white swooped and pecked. A magpie had seen an opportunity that none of us unwilling spectators could bear to watch. Nor could we look away. The pigeon, we realised as one mind, was not destined to starve to death, but to be eaten alive. Something the pigeon knew instantly. The magpie swooped again, then a third time, provoking the pigeon into ever more desperate beating of its wings. The magpie found a perch near enough to peck at its leisure, targeting the head and eyes. We tried to turn our eyes away but were irresistibly drawn back. As we began to lose hope, the pigeon made one superlative effort and broke loose. The relief swept through the light air of the piazza, drawing a soft ripple of applause from those of us who had borne witness to one soul who had raged successfully against the dying of the light.


Further Reading

Fischer, D., Fücker, Sonja, editor, & Selm, Hanna, editor. (2022). Narrating sustainability through storytelling. Available in the British Library through Non-Print Legal Deposit
Friedmann, H. (1946). The symbolic goldfinch: Its history and significance in European devotional art. (Bollingen series; 7). Washington: Pantheon Books. Available in the British Library at shelfmark 7868.ff.36
Macfarlane, R. (2019). Underland: A deep time journey. Penguin. Available in the British Library through Non-Print Legal Deposit or at shelfmark YK.2020.a.1303
Moreton, C. (2007). Maid and the Magpie An Interesting Tale Founded on Facts. Project Gutenberg.
Nanson, A. (2021). Storytelling and Ecology : Empathy, Enchantment and Emergence in the Use of Oral Narratives. (Bloomsbury Advances in Ecolinguistics). Available in the British Library through Non-Print Legal Deposit
Thomas, D. (1952). Collected Poems, 1934-1952. [With a portrait.]. J. M. Dent & Sons, 1952. Available in the British Library at shelfmark 11613.bb.15.
Woodward, I., Arnold, Richard, and London Natural History Society. (2017). The London bird atlas. John Beaufoy Publishing Ltd. Available in the British Library at shelfmark YKL.2019.b.1828

By Huw Rowlands, Cataloguer and Processing Coordinator, Western Heritage Collection
Photographs by Greg Smith, ESTC Support, Content and Metadata Processing South

01 August 2023

Wild British Library: The woodpigeon: from woods to trees

A woodpigeon, a plump grey bird with a pinkish breast, is seen in close up perched on a wall
Figure 1 Woodpigeon (Columba palumbus) is alert, ready to take off (13 June 2023) British Library, St Pancras Photo: Andrea Deri


The woodpigeon (Columba palumbus L.) is one of the most noticeable birds around the British Library’s St Pancras site.

Left: a pigeon is seen from a distance perched on a wall at the British Library. Right: a pigeon is seen standing on the ground on wooden slatted flooring
Figure 2 Woodpigeon perches high (11 June 2023) and waddles low, searching for food under the terrace tables (22 May 2022) British Library, St Pancras Photo: Andrea Deri


This affable plump bird can be seen perching high on building edges, waddling low on the ground in search of food or engaged in a variety of social behaviour [1]: courtship, posturing, wing fight, thrashing out of the foliage in a conceding flight, or flying over with powerful wingbeats [2] [Fig.1-5, 11].

Two pigeons are seen on the ground facing each other, one with a crest erected and with its head beneath the other's
Figure 3 Woodpigeon courtship (12 June 2023) British Library, St Pancras, Photo: Andrea Deri


It is not only their sociability and size [3], about 500 grams, the largest [4] pigeon in the UK avifauna, but also their sheer number that makes the woodpigeon easy to spot throughout the year. According to The London Bird Atlas [5] the woodpigeon was the most abundant bird during the winter and breeding time surveys in 2008-13.

Left: a pigeon is seen close up among green leaves. Right: a similar view from a distance
Figure 4 Woodpigeon nest in ivy (Hedera helix) (11 June 2022) and in Virginia creeper (Parthenocissus quinquefolia) (7 July 2023) British Library, St Pancras, Photo: Andrea Deri


Woodpigeons have made their home around the British Library in London. They nest in the dense foliage of woody climbers: common ivy (Hedera helix) [6] and Virginia creeper (Parthenocissus quinquefolia) [7]. One of their fledglings was spotted on a chair in March 2023.

A fledgling woodpigeon (paler coloured and thinner than the adult) is seen perched on the back of a metal chair against a background of greenery
Figure 5 Woodpigeon fledgling near a nest in ivy (22 March 2023) British Library, St Pancras, Photo: Andrea Deri


Ronald Keir Murton’s monograph [8] and PhD thesis [9] provide comprehensive overviews of the woodpigeon’s biology, ecology, and behaviour.

Timeline: from woods to trees

The woodpigeon, as its name suggests, was once only associated with forests and woods. The timeline of its journey from woods to trees, from the countryside to the city is revealed by ornithologists’ observations:

1544 – 1884 – 1888 – 1891 – 1957 – 2010 – 2014 – 2023
Woods                     Trees

1544 - William Turner, a physician and natural historian, referred to the woodpigeon as the “coushot” or “ringged dove” and described it as a forest dwelling bird [Fig. 6-7].

Pages of a printed book in Latin, with the English words "a ringged dove" underlined in ink
Figure 6 The woodpigeon’s name in Greek, Latin, English and German in William Turner’s Avium praecipuarum quarum apud Plinium et Aristotlem mentio est brevis & succinta historia (1544): British Library, Shelfmark 976.f.4


Turner’s treatise [10], written in Latin, is considered the oldest printed book dedicated to birds. It lists bird species mentioned by Aristotle and Pliny with Turner’s own observations.

Both the Latin editions (1544, 1823) [11] and the English translation (1903) [12] are available online.

Two pages of a hardbound book, held down with a book snake.
Figure 7 Description of the woodpigeon in William Turner’s Avium praecipuarum quarum apud Plinium et Aristotlem mentio est brevis & succinta historia (1544): British Library, Shelfmark 976.f.4


Turner’s bird book is a small thin volume that sits comfortably in the hand, without illustrations and pagination. [Fig. 7-8]

The spine of an old hardbacked book, and the closed book next to a paperback and a pair of binoculars
Figure 8 Spine, size comparison with a recent birdwatcher’s guide & binoculars: William Turner’s Avium praecipuarum quarum apud Plinium et Aristotlem mentio est brevis & succinta historia (1544): British Library, Shelfmark 976.f.4


The British Library has two copies of Turner’s bird book. The copy at shelfmark 976.f.4 is particularly interesting because it belonged probably to Sir Hans Sloane [13], owner of one of the British Library’s founding [14] and named collections [15], now controversial due to his wife's inheritance of money obtained from slave-worked Jamaican sugar plantations. The black octagonal stamp “Museum Britannicum” on the title page verso was intended to distinguish Sloane’s books alone but later acquisitions were also stamped with it. [Fig.9]

The title page of a book, held open with a book snake. On the opposite page is a stamp of a horizontally stretched hexagon containing, in capitals, the words MVSEUM BRITANICVM
Figure 9 The black octagonal stamp “Museum Britannicum” marked items of the Sloane Collection including William Turner’s Avium praecipuarum quarum apud Plinium et Aristotlem mentio est brevis & succinta historia (1544): British Library, Shelfmark 976.f.4

 

1884 - Henry Seebohm [16], steel manufacturer and amateur ornithologist, portrayed the woodpigeon a “common resident in the wooded districts” of England and Wales, Scotland and Ireland, except those tame ones living in Paris’ and Berlin’s parks. [Fig. 10]

The title page and a text page of a printed hardback book
Figure 10 Henry Seebohm: A history of British Birds with coloured illustrations of their eggs, 4 volumes (1884): title page and page 396 in vol. 2, British Library, Shelfmark 7287.c.2.


1888 & 1891 - Tristram-Valentine [17] solicitor and amateur ornithologist, was genuinely surprised to see woodpigeons in London:

“Probably the last bird that a countryman would expect to find in London would be the ringdove or, as it is more commonly called, the woodpigeon; yet this bird, though not by any means common, is generally to be seen in the Parks, and certainly claim to be included in any list of London birds […].” (25 February 1888; page 193)

“It is certainly curious that a bird naturally so wild and wary as the wood-pigeon should so alter its habit as to live the year through in parks even as large as those of the West End, surrounded as they are by miles of streets and buildings.” (25 February 1888; page 193)

Three years later transformative change happened. The woodpigeon became “the most noticeable” London bird according to Tristram-Valentine:

“The enormous increase during the last few years in the number of wood-pigeons frequenting the London Parks must have struck the least observant. Formerly a few pairs bred there every year, Kensington Gardens and the grounds of Buckingham Palace being their favourite nesting-places ; but a few years since their numbers began to increase, and they are now— sparrows always excepted—the commonest of London birds, and are certainly, without any exception, the most noticeable.“ (4 July 1891 page 238)

1957 – The Committee of the London Natural History Society [18] referred to the woodpigeon as “common resident, breeding throughout the [London] Area.”

2010 – Robert A. Robinson [19], senior scientists of the British Trust for Ornithology (BTO) discussed the woodpigeon as a species of the towns and gardens habitats, not in woodlands and scrubs. Robinson listed the woodpigeon as one of the eight bird species typical of urban and suburban areas, “house sparrow, starling, blackbird, magpie, collared dove, greenfinch, carrion crow, and increasingly woodpigeon.”

2023 - BTO also refers to the woodpigeon as a common bird that can be seen across a range of habitats [3]. In addition to the woodpigeon’s biology and ecology, BTO also discusses various anthropogenic drivers of the woodpigeon’s population increase, 153% (1967-2020).

In the 2023 RSPB Big Garden Birdwatch [20] the woodpigeon ranked fourth. It was seen in 76.8% of gardens (after the robin 84.5%, blackbird 82.5%, and blue tit 77.5%). This list shows that the woodpigeon is one of the most noticeable birds not only at the British Library’s St Pancras site but also in the UK.

A pigeon sitting on a concrete slab, its legs and feet invisible.
Figure 11 Woodpigeon resting (13 June 2023) British Library, St Pancras Photo: Andrea Deri


People and wildlife

When naturalists take note of their observations, they record not only what species they see, where, when and in what numbers, but also their thoughts and feelings about wildlife as some of the quotes above illustrate. This human connection makes their stories not only appealing but also indicative of their, the birdwatchers’ relationship with wildlife.
Given its size, tameness, and uninhibited social life the woodpigeon offers one of the best opportunities, if not the best, for people, all of us, to watch their behaviour closely, learn about their daily and seasonal routines, and connect with these birds.

The woodpigeon’s influence on people’s connection with wildlife cannot be underestimated.

Posted by Andrea Deri, Cataloguer

Acknowledgement

Ann McDermott, ESTC Cataloguer, Early Printed Collections, British Library for providing resources related to William Turner’s Avium (1544).
Dr Karen Limper-Herz, Lead Curator, Incunabula and Sixteenth Century Printed Books and Greg Smith, ESTC Support for their suggestions.

References and further readings [British Library shelfmark]

All URLs were accessed on 10 July 2023.

[1] Gomez, Africa. ‘Woodpigeon Calls and Displays’. The Rattling Crow (blog), 27 March 2017. http://therattlingcrow.blogspot.com/2017/03/woodpigeons-calls-and-displays.html
[2] Pedley, William. ‘Woodpigeon Wingbeats’, 26 October 1975. https://www.bl.uk/collection-items/woodpigeon-columba-palumbus-wingbeats.
[3] BTO. ‘Woodpigeon (Columba palumbus) (Linnaeus, 1758)’. BirdFacts: Key information about the UK’s birds and their changing fortunes, based on data collected by BTO and partner organisations., 2023. https://www.bto.org/understanding-birds/birdfacts/woodpigeon
[4] BTO. ‘Woodpigeon (Columba Palumbus)’, 2023. https://www.bto.org/our-science/projects/gbw/gardens-wildlife/garden-birds/a-z-garden-birds/wood-pigeon
[5] Woodward, Ian D., Richard Arnold, and Neil Smith. The London Bird Atlas. [London], Oxford: London Natural History Society; John Beaufoy Publishing, 2017. [YKL.2019.b.1828]
[6] Plant Atlas 2020. ‘Common & Atlantic Ivy (Hedera Helix s.l.)’, 2020. https://plantatlas2020.org/atlas/2cd4p9h.95p1tn
[7] Plant Atlas 2020. ‘Virginia-Creeper (Parthenocissus Quinquefolia (L.) Planch.)’, 2020. https://plantatlas2020.org/atlas/2cd4p9h.n0d
[8] Murton, R. K. The Wood-Pigeon. The New Naturalist. London: Collins, 1965. [(B) GD 29 (C5)]
[9] Murton, R. K. ‘The Ecology of Wood-Pigeon Populations with Special Reference to Their Breeding Biology’. PhD, University of Liverpool, 1962. https://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.287121
[10] Turner, William. Avium Praecipuarum Quarum apud Plinium et Aristotlem Mentio Est Brevis & Succinta Historia, 1544. [976.f.4 and 954.b.11]
[11] Turner, William. Avium Praecipuarum Quarum apud Plinium et Aristotlem Mentio Est Brevis & Succinta Historia, 1544. https://books.google.co.uk/books?id=s106AAAAcAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=thumbnail&q&f=false
[11] Turner, William. Avium Praecipuarum Quarum apud Plinium et Aristotlem Mentio Est Brevis & Succinta Historia. Cantabrigiae: typis academicis excudebat Joan Smith, 1823. https://access.bl.uk/item/viewer/ark:/81055/vdc_100036705079.0x000001#?c=0&m=0&s=0&cv=0&xywh=-1142%2C-120%2C3535%2C2346
[12] Turner, William. Turner on Birds?: A Short and Succinct History of the Principal Birds Noticed by Pliny and Aristotle First Published by Doctor William Turner, 1544. Translated by A. H. Evans. Cambridge?: University Press, 1903. [7285.dd.9.] https://doi.org/10.5962/bhl.title.160035.
[13] British Library. ‘Sloane Printed Books Catalogue’, 1 February 2023. https://www.bl.uk/projects/sloane-printed-books
[14] British Library. ‘The Foundation Collections’, 2023. https://www.bl.uk/catalogues/illuminatedmanuscripts/TourCollFound.asp
[15] British Library. ‘Major Named Collections of Printed Books’, 2023. https://www.bl.uk/collection-guides/major-named-collections-of-printed-books-now-in-the-british-library
[16] Seebohm, Henry. A History of British Birds, with Coloured Illustrations of Their Eggs. 4
volumes vols. London: R. H. Porter, 1883-85. [7287.c.2.], also online at https://www.biodiversitylibrary.org/bibliography/12367
[18] Tristram-Valentine, J.T. London Birds and Beasts. London, 1895. [7206.bb.20]
[19] Homes, R.C. The Birds of the London Area since 1900. The New Naturalist. London:
Collins, 1957. pp. 211-212 [W.P. 12018/12]
[20] Robinson, Robert A. ‘State of Bird Populations in Britain and Ireland’. In Silent Summer: The State of Wildlife in Britain and Ireland, edited by Norman Maclean, 281–318. Cambridge?; New York: Cambridge University Press, 2010. [YK.2010.a.19902]
[21] RSPB. ‘The Results from across the UK Have Landed!’ Big Garden Birdwatch, 2023. https://www.rspb.org.uk/get-involved/activities/birdwatch/