Intensive Agriculture Blamed for Bird Population Decline in Spain

Recent figures show an alarming decline in the populations of important bird species in Spain as intensive agriculture transforms the country's landscape.
The rufous-tailed scrub robin (Cercotrichas galactotes)
By Simon Roots
Feb. 4, 2023 17:52 UTC

The lat­est Atlas of Breeding Birds in Spain shows a pop­u­la­tion decline of about 27 per­cent in birds linked to agri­cul­tural envi­ron­ments.

The inten­si­fi­ca­tion of farm­ing meth­ods is the dri­ving force, accord­ing to SEO/BirdLife, with super-high-den­sity olive groves being par­tic­u­larly detri­men­tal to key species.

SEO/BirdLife noted that although such a sig­nif­i­cant aver­age decline is deeply con­cern­ing, many indi­vid­ual species have suf­fered even more sig­nif­i­cant losses.

See Also:Bans on Night Harvesting Have Alleviated Threat to Migratory Birds

The rufous-tailed scrub robin, for exam­ple, saw a decline of nearly 95 per­cent since 2003; the lit­tle bus­tard, about 69 per­cent from 1998 to 2018; and the black-bel­lied sand­grouse, 34 per­cent between 2005 and 2009.

The most sig­nif­i­cant over­all threats to all three of these species in Spain are rooted in wide­spread changes to agri­cul­tural meth­ods.

Previous research showed that farm­land is the most impor­tant habi­tat for bird con­ser­va­tion in Europe, har­bor­ing more than 50 per­cent of bird species in the European Union and 55 per­cent of European bird species on the International Union for Conservation of Nature’s Red List.

IUCN Red List

The IUCN Red List is a com­pre­hen­sive inven­tory of the global con­ser­va­tion sta­tus of plant, ani­mal and fun­gus species. It serves as a global barom­e­ter of the health of the world’s bio­di­ver­sity and pro­vides sci­en­tific infor­ma­tion that can help guide con­ser­va­tion action.

The Iberian penin­sula is par­tic­u­larly impor­tant to many endan­gered and vul­ner­a­ble species, with some 60 per­cent of the sur­viv­ing global pop­u­la­tion of the great bus­tard now con­fined to Spain and Portugal, for exam­ple.

The inten­si­fi­ca­tion of agri­cul­ture has changed the Spanish land­scape rad­i­cally in recent decades. With increased pro­duc­tiv­ity as its sole dri­ving force, it has led to the mas­sive expan­sion of mono­cul­tures, the reduc­tion of wild and fal­low areas, the trans­for­ma­tion of large areas of dry land into irri­gated land, and the wide­spread use of pes­ti­cides and her­bi­cides.

These fac­tors have decreased the quan­tity and qual­ity of ter­ri­tory avail­able to wildlife in gen­eral and birds in par­tic­u­lar.

Monocultures, by def­i­n­i­tion, reduce bio­di­ver­sity, lead­ing to fewer plants with seeds as a food source, fewer places to breed and less shel­ter from preda­tors and the ele­ments.

In the case of super-high-den­sity olive groves, immense tracts of land are used mostly for uni­form rows of olive trees and much of the other veg­e­ta­tion is removed.

Not only does this cre­ate an envi­ron­ment hos­tile to wildlife, but it also involves the destruc­tion of the exist­ing envi­ron­ment, lead­ing to the death or dis­place­ment of the entire local ecosys­tem.

As many species of bird are migra­tory, com­plex and long-estab­lished migra­tion routes can also be inter­rupted or irrev­o­ca­bly bro­ken.

Over the same period, the sig­nif­i­cant decline in European insects has also affected bird pop­u­la­tions since approx­i­mately 60 per­cent of all known bird species are at least partly insec­tiv­o­rous.


A 2017 analy­sis esti­mated a sea­sonal decline of 76 per­cent and a mid-sum­mer decline of 82 per­cent in fly­ing insect bio­mass since 1990.

The exact causes of this decline remain unre­solved. Still, the study’s authors noted that agri­cul­tural inten­si­fi­ca­tion, includ­ing the dis­ap­pear­ance of field mar­gins and new crop pro­tec­tion meth­ods, has been asso­ci­ated with an over­all decline of bio­di­ver­sity in plants, insects, birds and other species in the cur­rent land­scape.”

In addi­tion to the gen­eral decline of fly­ing insects, inten­sive farm­ing meth­ods result in dras­ti­cally reduced num­bers of local ground prey species such as spi­ders, cater­pil­lars and grasshop­pers.

This results from the same fac­tors that make the envi­ron­ments hos­tile to the birds, most notably lack of ground cover, an engi­neered mono­cul­ture, uni­for­mity of land­scape and increased use of arti­fi­cial her­bi­cides, pes­ti­cides and fer­til­iz­ers.

The land­scape has been fur­ther altered by the con­struc­tion of vast indus­trial and trans­port infra­struc­tures and, more recently, renew­able energy instal­la­tions such as pho­to­voltaic and wind farms.

Due to their com­mer­cial nature, many of these projects are sited on land deemed unpro­duc­tive” by humans but vital to other species as their nat­ural habi­tats.

Discussing the impli­ca­tions for the new Common Agricultural Policy (CAP) in 2022, José Eugenio Gutiérrez, del­e­gate of SEO/BirdLife in Andalusia and head of the Life Olivares Vivos+ project, said that to con­serve our nat­ural her­itage… stop­ping this trans­for­ma­tion of farm­land into woody crop­land or solar pho­to­voltaic plants is a top pri­or­ity that must go through ade­quate strate­gic plan­ning at the ter­ri­to­r­ial level, and com­pli­ance with the envi­ron­men­tal objec­tives of the new CAP.”

The Olivares Vivos farm­ing model, based on research car­ried out by the ecol­ogy depart­ment of the University of Jaén and the Arid Zones Experimental Station of the Spanish National Research Council seeks to reduce the neg­a­tive envi­ron­men­tal impact of olive farm­ing while increas­ing bio­di­ver­sity.

This is accom­plished by intro­duc­ing non-crop native species, installing sup­port infra­struc­tures for fauna such as ponds, nest­ing boxes, and fenc­ing posts; and restor­ing so-called unpro­duc­tive areas” in olive groves such as gul­lies, streams, tracks, and walls.

SEO/BirdLife and the Life Olivares Vivos+ project have made numer­ous rec­om­men­da­tions to regional, national, and E.U. gov­ern­ment bod­ies regard­ing the need to con­sider the habi­tats of agri­cul­tural bird species when cre­at­ing agri­cul­tural and envi­ron­men­tal poli­cies.


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