Total OH reactivity over the Amazon rainforest: variability with temperature, wind, rain, altitude, time of day, season, and an overall budget closure

Abstract. The tropical forests are Earth's largest source of biogenic volatile organic compounds (BVOCs) and thus also the largest atmospheric sink region for the hydroxyl radical (OH). However, the OH sink above tropical forests is poorly understood, as past studies have revealed large unattributed fractions of total OH reactivity. We present the first total OH reactivity and volatile organic compound (VOC) measurements made at the Amazon Tall Tower Observatory (ATTO) at 80, 150, and 320 m above ground level, covering two dry seasons, one wet season, and one transition season in 2018–2019. By considering a wide range of previously unaccounted for VOCs, which we identified by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS), the unattributed fraction was with an overall average of 19 % within the measurement uncertainty of ∼ 35 %. In terms of seasonal average OH reactivity, isoprene accounted for 23 %–43 % of the total and oxygenated VOCs (OVOCs) for 22 %–40 %, while monoterpenes, sesquiterpenes, and green leaf volatiles combined were responsible for 9 %–14 %. These findings show that OVOCs were until now an underestimated contributor to the OH sink above the Amazon forest. By day, total OH reactivity decreased towards higher altitudes with strongest vertical gradients observed around noon during the dry season (−0.026 s−1 m−1), while the gradient was inverted at night. Seasonal differences in total OH reactivity were observed, with the lowest daytime average and standard deviation of 19.9 ± 6.2 s−1 during a wet–dry transition season with frequent precipitation; 23.7 ± 6.5 s−1 during the wet season; and the highest average OH reactivities during two dry-season observation periods with 28.1 ± 7.9 s−1 and 29.1 ± 10.8 s−1, respectively. The effects of different environmental parameters on the OH sink were investigated, and quantified, where possible. Precipitation caused short-term spikes in total OH reactivity, which were followed by below-normal OH reactivity for several hours. Biomass burning increased total OH reactivity by 2.7 to 9.5 s−1. We present a temperature-dependent parameterization of OH reactivity that could be applied in future models of the OH sink to further reduce our knowledge gaps in tropical-forest OH chemistry.

Download Full-text

Total OH reactivity over the Amazon rainforest: variability with temperature, wind, rain, altitude, time of day, season, and an overall budget closure

10.5194/acp-2020-752 ◽

2020 ◽

Author(s):

Eva Y. Pfannerstill ◽

Nina G. Reijrink ◽

Achim Edtbauer ◽

Akima Ringsdorf ◽

Nora Zannoni ◽

...

Keyword(s):

Tropical Forests ◽

Ground Level ◽

Time Of Day ◽

Green Leaf Volatiles ◽

Dry Season ◽

Amazon Forest ◽

Wet Season ◽

Leaf Volatiles ◽

Transition Season ◽

Wide Range

Abstract. The tropical forests are Earth’s largest source of biogenic volatile organic compounds (BVOCs) and thus also the largest atmospheric sink region for the hydroxyl radical (OH). However, the OH sink above tropical forests is poorly understood, as past studies revealed large unattributed fractions of total OH reactivity. We present the first total OH reactivity and VOC measurements made at the Amazon Tall Tower Observatory (ATTO) at 80, 150, and 320 m above ground level, covering two dry seasons, one wet and one transition season in 2018–2019. By considering a wide range of previously unaccounted for VOCs, which we identified by PTR-ToF-MS, the unattributed fraction was with an overall average of 19 % within the measurement uncertainty of ~ 35 %. In terms of seasonal average OH reactivity, isoprene accounted for 23–43 % of the total, oxygenated VOCs (OVOCs) for 22–40 %, while monoterpenes, sesquiterpenes, and green leaf volatiles combined were responsible for 9–14 %. These findings show that OVOCs were until now an underestimated contributor to the OH sink above the Amazon forest. By day, total OH reactivity decreased towards higher altitudes with strongest vertical gradients observed around noon during the dry season (−0.026 s−1 m−1), while the gradient was inverted at night. Seasonal differences in total OH reactivity were observed, with the lowest daytime average and standard deviation of 19.9 ± 6.2 s−1 during a wet–dry transition season with frequent precipitation, 23.7 ± 6.5 s−1 during the wet season, and the highest average OH reactivities during two dry season observation periods with 28.1 ± 7.9 s−1 and 29.1 ± 10.8 s−1, respectively. The effects of different environmental parameters on the OH sink were investigated, and quantified, where possible. Precipitation caused short-term spikes in total OH reactivity, which were followed by below-normal OH reactivity for several hours. Biomass burning increased total OH reactivity by 2.7 s−1 to 9.5 s−1. We present a temperature-dependent parameterization of OH reactivity that could be applied in future models of the OH sink to further reduce our knowledge gaps in tropical forest OH chemistry.

Download Full-text

Agricultural crops in the diet of bearded capuchin monkeys, Cebus libidinosus Spix (Primates: Cebidae), in forest fragments in southeast Brazil

Revista Brasileira de Zoologia ◽

10.1590/s0101-81752008000100006 ◽

2008 ◽

Vol 25 (1) ◽

pp. 32-39 ◽

Cited By ~ 38

Author(s):

Carlos Henrique de Freitas ◽

Eleonore Z. F. Setz ◽

Alba R. B. Araújo ◽

Nivar Gobbi

Keyword(s):

Fruit Production ◽

Dry Season ◽

Southeastern Brazil ◽

Capuchin Monkeys ◽

Home Ranges ◽

Forest Fragments ◽

Wet Season ◽

Plant Matter ◽

Wide Range ◽

Cebus Libidinosus

Capuchin monkeys occupy a wide range of habitats where they feed on fruits, arthropods, and vertebrates. Their large home ranges (80-900 ha) suggest that living in forest fragments may challenge their adaptability. We identified and quantified the main food items of Cebus libidinosus Spix, 1823 in forests fragments (100 ha) in southeastern Brazil. We recorded the feeding activities of two groups using scan sampling over a 13-month period. The diet was composed of fruits, crops, animal prey, seeds, plant matter and undetermined. Fruit was eaten more in the wet season than in the dry season, and maize and sugar cane consumption peaked in the early dry season. The proportion of fruit in the diet was positively correlated with fruiting intensity of zoochorous trees. The plant diet included 54 species, with maize, Rhamnidium elaeocarpus, Acrocomia aculeata, Guazuma ulmifolia and Cariniana, being most important. Although dietary composition and diversity were similar to capuchins in larger forest fragments, feeding on crops attained higher percentages at times when zoochorous fruit production was low in fragments.

Download Full-text

KOMPOSISI DAN FLUKTUASI HASIL TANGKAPAN TUGUK DI SUNGAI LEMPUING, SUMATERA SELATAN

Jurnal Penelitian Perikanan Indonesia ◽

10.15578/jppi.15.2.2009.105-112 ◽

2017 ◽

Vol 15 (2) ◽

pp. 105

Author(s):

Dharmadi Dharmadi ◽

Endi Setiadi Kartamihardja ◽

Agus Djoko Utomo ◽

Dian Oktaviani

Keyword(s):

Fish Species ◽

Descriptive Analysis ◽

Dry Season ◽

Survey Method ◽

Wet Season ◽

River Waters ◽

Transition Season ◽

Fish Catch ◽

Catch Composition ◽

Mystus Nemurus

Tujuan penelitian ini adalah untuk mengetahui komposisi dan fluktuasi hasil tangkapan tuguk pada periode berbeda yang dioperasikan di Sungai Lempuing, Sumatera Selatan. Kegiatan penelitian dilaksanakan dengan metode survei pada periode musim peralihan penghujan sampai dengan kemarau (bulan April), musim kemarau (bulan Juni) dan musim penghujan (bulan Desember) tahun 2007. Komposisi jenis ikan dan hasil tangkapan diperoleh berdasarkan pada data pengambilan contoh pada saat ke lapangan dan data harian hasil tangkapan tuguk yang dicatat oleh 3 orang enumerator. Data dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa hasil tangkapan tuguk berbeda menurut periode waktu. Hasil tangkapan terdiri atas 11 jenis ikan untuk musim peralihan dan kemarau masing-masing berkisar 400-450 kg per unit per hari (rata-rata 411,2+14,1 kg per unit per hari) dan 250-300 kg per unit per hari (rata-rata 263,3+13,4 kg per unit per hari) dan 13 jenis ikan pada musim penghujan (bulan Desember) berkisar 700-750 kg per unit per hari (rata-rata 724,8+17,7 kg per unit per hari). Hasil tangkapan didominansi oleh jenis ikan lele (Clarias melanoderma) dan baung (Mystus nemurus). Selama penelitian, kandungan oksigen terlarut di perairan relatif rendah, berkisar 2-4 mg per l, namun dapat ditolelir oleh kelompok jenis ikan rawa (black fish). This research proposed to observed a catch composition and fluctuation of filtering device in different periods operated in the Lempuing River, South Sumatera. The research was conducted using survey method at a respective month of April (transition season), June (dry season) and December 07 (wet season). Fish composition and catch of tuguk were noted during survey and based on recording 3 enumerators. Descriptive analysis was used in this study. The results show that the catch of filtering device differed on diferent season periodes. A number of 11 fish species was caught at a respective season of transition season (April) of 400-450 kg per unit per day (average=411.2+14,1 kg per unit per day), dry season (June) of 250 300 kg per unit per day (average = 263,3+13,4 kg per unit per day), whilst at rainy season (December), fish catch composed of 13 fish species, ranging 700-750 kg per unit per day or (average = 724.8+17.7 kg per unit per day). Clarias melanoderma and Mystus nemurus were dominantly caught in the Lempuing River waters. During observation, dissolved oxygen content was relatively low (2-4 mg per l), that but could be tolerated by black fish.

Download Full-text

Cloud macrophysical properties from airborne observations during EUREC4A

10.5194/egusphere-egu2020-11106 ◽

2020 ◽

Author(s):

Heike Konow ◽

Marcus Klingebiel ◽

Felix Ament

Keyword(s):

Deep Convection ◽

Dry Season ◽

Trade Wind ◽

Special Focus ◽

Wet Season ◽

Diurnal Cycles ◽

Cloud Radar ◽

Wide Range ◽

Macrophysical Properties ◽

Different Response

Trade wind cumulus clouds are the predominant cloud type over the tropical Atlantic east of the island of Barbados. Parameters describing their macroscopic shape can help characterizing and comparing general features of clouds. This characterizing will indirectly help to constrain estimates of climate sensitivity, because models with different structures of trade wind cumuli feature different response to increased CO2 contents.Two aircraft campaigns with the HALO (High Altitude LOng range) aircraft took place in the recent past in this region: NARVAL-South (Next-generation Aircraft Remote-Sensing for VALidation studies) in December 2013, during the dry season, and NARVAL2 in August 2016, during the wet season. During these two campaigns, a wide range of cloud regimes from shallow to deep convection were sampled. This past observations are now extended with observations from this year&#8217;s measurement campaign EUREC4A, again during the dry season. EUREC4A is endorsed as WCRP capstone experiment and the synergy of four research aircraft, four research vessels and numerous additional observations will provide comprehensive characterizations of trade wind clouds and their environment.Part of the NARVAL payload on HALO is a 35 GHz cloud radar, which has been deployed on HALO on several missions since 2013. These cloud radar measurements are used to segment individual clouds entities by applying connected component analysis to the radar cloud mask. From these segmented individual clouds, macrophysical parameters are derived to characterize each individual cloud. This presentation will give an overview of the cloud macrophysics observed from HALO during EUREC4A. Typical macrophysical parameters, i.e. cloud depth, cloud length, cloud fraction, are analyzed. We will relate these to observations from past campaigns and assess the representativeness of EUREC4A. As special focus of the EUREC4A campaign, measurements will be performed during different times of the day to detect diurnal cycles. Macrophysical parameters can be used to characterize changes over the day and cloud scenes of similar clouds types can be identified.

Download Full-text

Variability of overhead volatile organic compounds in clonal tea (Camellia sinensis) and their influence on red crevice mite (Brevipalpus phoenicis Geijskes) infestations

International Journal of Tea Science ◽

10.20425/ijts.v0iof.9574 ◽

2016 ◽

Author(s):

Jenipher A. Odak ◽

P. Okinda Owuora ◽

Lawrence O.A. Mang’uro ◽

Evelyn Cheramgoi ◽

And Francis N. Wachira

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Aromatic Compounds ◽

Green Leaf Volatiles ◽

Leaf Volatiles ◽

Hexenyl Acetate ◽

Volatile Organic ◽

Brevipalpus Phoenicis ◽

Tea Production ◽

Breeding Selection

Tea production in Kenya is under threat due to red crevice mites (Brevipalpus phoenicis) infestations during droughts. Cultural pests control practices, e.g. use of resistant/tolerant cultivars are used in their control since pesticide use is prohibited. Plants release volatile organic compounds (OVOCs) that may influence susceptibility/resistance to pest infestations. OVOCs profiles released by 11 tea cultivars were evaluated to assess relationship between OVOCs and cultivar tolerance/susceptibility to B. phoenicis. Five clones were susceptible, with high B. phoenicis infestations while four clones were resistant, exhibiting low infestation levels. The infestations were linearly correlated to (E)-2-hexenal, (Z)-3-hexenal (p≤0.001), (Z)-3-hexenol, (Z)-3-hexenyl acetate, linalool, germacrene D, sum of green leaf volatiles (GLVs) (p≤0.01), 1-pentene-3-ol, hexanal, indole and (E)-β-ocimene (p≤0.05) levels. Most of aromatic compounds, some terpenoids compounds and sum of aromatic compounds were inversely (p≤0.05) correlated with B. phoenicis infestations. Susceptible varieties to B. phoenicis emitted high amounts of GLVs, especially (E)-2-hexenal, (Z)-3-hexenal, (Z)-3-hexen-1-ol and (Z)-3-hexenyl acetate. Results demonstrate that OVOCs profile may provide selection criteria for cultivars resistant to B. phoenicis infestations. Resistant cultivars are recommended for commercial exploitation in red crevice mites prone areas while breeding/selection programmes should incorporate OVOCs profiles to develop tea cultivars that resist red crevice mites attack.

Download Full-text

Diel and seasonal changes of biogenic volatile organic compounds within and above an Amazonian rainforest

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-3359-2015 ◽

2015 ◽

Vol 15 (6) ◽

pp. 3359-3378 ◽

Cited By ~ 45

Author(s):

A. M. Yáñez-Serrano ◽

A. C. Nölscher ◽

J. Williams ◽

S. Wolff ◽

E. Alves ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Ambient Air ◽

Dry Season ◽

Solar Irradiation ◽

Biogenic Volatile Organic Compounds ◽

Wet Season ◽

Mixing Ratios ◽

Volatile Organic ◽

Amazonian Rainforest

Abstract. The Amazonian rainforest is a large tropical ecosystem, which is one of the last pristine continental terrains. This ecosystem is ideally located for the study of diel and seasonal behaviour of biogenic volatile organic compounds (BVOCs) in the absence of local human interference. In this study, we report the first atmospheric BVOC measurements at the Amazonian Tall Tower Observatory (ATTO) site, located in central Amazonia. A quadrupole proton-transfer-reaction mass spectrometer (PTR-MS), with seven ambient air inlets, positioned from near ground to about 80 m (0.05, 0.5, 4, 24, 38, 53 and 79 m above the forest floor), was deployed for BVOC monitoring. We report diel and seasonal (February–March 2013 as wet season and September 2013 as dry season) ambient mixing ratios for isoprene, monoterpenes, isoprene oxidation products, acetaldehyde, acetone, methyl ethyl ketone (MEK), methanol and acetonitrile. Clear diel and seasonal patterns were observed for all compounds. In general, lower mixing ratios were observed during night, while maximum mixing ratios were observed during the wet season (February–March 2013), with the peak in solar irradiation at 12:00 LT (local time) and during the dry season (September 2013) with the peak in temperature at 16:00 LT. Isoprene and monoterpene mixing ratios were the highest within the canopy with a median of 7.6 and 1 ppb, respectively (interquartile range (IQR) of 6.1 and 0.38 ppb) during the dry season (at 24 m, from 12:00 to 15:00 LT). The increased contribution of oxygenated volatile organic compounds (OVOCs) above the canopy indicated a transition from dominating forest emissions during the wet season (when mixing ratios were higher than within the canopy), to a blend of biogenic emission, photochemical production and advection during the dry season when mixing ratios were higher above the canopy. Our observations suggest strong seasonal interactions between environmental (insolation, temperature) and biological (phenology) drivers of leaf BVOC emissions and atmospheric chemistry. Considerable differences in the magnitude of BVOC mixing ratios, as compared to other reports of Amazonian BVOC, demonstrate the need for long-term observations at different sites and more standardized measurement procedures, in order to better characterize the natural exchange of BVOCs between the Amazonian rainforest and the atmosphere.

Download Full-text

Current Population Status and Activity Pattern of Lesser Flamingos (Phoeniconaias minor) and Greater Flamingo (Phoenicopterus roseus) in Abijata-Shalla Lakes National Park (ASLNP), Ethiopia

International Journal of Biodiversity ◽

10.1155/2014/295362 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Tewodros Kumssa ◽

Afework Bekele

Keyword(s):

Population Size ◽

Activity Pattern ◽

Habitat Preference ◽

Time Of Day ◽

Dry Season ◽

Population Status ◽

Wet Season ◽

Current Population ◽

Dry Seasons ◽

Wet And Dry Seasons

A study of the population status, habitat preference, and activity pattern of nonbreeding flamingos was carried out in Lakes Abijata, Shalla, and Chitu, part of the Great Rift Valley, Ethiopia, from 2011 to 2013. The current population status and habitat preference of flamingos in the area are still poorly known. Likewise, data on diurnal and seasonal activity pattern of the species are scarce and this leads to the misunderstanding of how Flamingos use local wetlands throughout the different seasons. Data regarding population size and activity pattern were gathered during the wet and dry seasons. Point-count method was used to estimate the population size. Behaviors were recorded using scan sampling techniques. A total of 53671 individuals representing two species of flamingo were counted during both wet and dry seasons from the three lakes. There were more flamingos during the dry season than the wet season in Lake Abijata contrary to Lakes Shalla and Chitu during the wet season. Lesser flamingos (Phoeniconaias minor) were the most abundant species comprising 95.39%, while Greater Flamingos (Phoenicopterus roseus) accounted for 4.61% of the total population. Lake Abijata is the major stronghold of Lesser Flamingos in the area. There was significant variation in the mean number of both species during the wet and dry season in the different study sites of the lake, respectively. The species were known to use varied habitats within the lakes. The Lesser Flamingo mainly preferred the shoreline and mudflat areas of the lakes. However, Greater Flamingo on several occasions showed preference to offshore area of the lakes. Seasonal average flock sizes were not similar between the species. There was a strong relationship between time allocated to each activity and time of day. Feeding activity varied among daylight hours and was higher in the evening (76.5%) and late morning (74.56%) and least during midday (54%). Some variations in activity breakdown were observed between time blocks and season. Conservation efforts in the park should include the wild flora and fauna not only of the land but also of the aquatic systems. The information in this study will be very useful for the future management of the species in the area.

Download Full-text

Seasonal and successional dynamics of size-dependent plant demographic rates in a tropical dry forest

PeerJ ◽

10.7717/peerj.9636 ◽

2020 ◽

Vol 8 ◽

pp. e9636

Author(s):

Irving Saenz-Pedroza ◽

Richard Feldman ◽

Casandra Reyes-García ◽

Jorge A. Meave ◽

Luz Maria Calvo-Irabien ◽

...

Keyword(s):

Climate Change ◽

Tropical Forests ◽

Dry Season ◽

Dry Forest ◽

Species Density ◽

Wet Season ◽

Successional Stage ◽

Size Dependent ◽

Demographic Rates ◽

Successional Stages

Tropical forests are globally important for biodiversity conservation and climate change mitigation but are being converted to other land uses. Conversion of seasonally dry tropical forests (SDTF) is particularly high while their protection is low. Secondary succession allows forests to recover their structure, diversity and composition after conversion and subsequent abandonment and is influenced by demographic rates of the constituent species. However, how these rates vary between seasons for different plant sizes at different successional stages in SDTF is not known. The effect of seasonal drought may be more severe early in succession, when temperature and radiation are high, while competition and density-dependent processes may be more important at later stages, when vegetation is tall and dense. Besides, the effects of seasonality and successional stage may vary with plant size. Large plants can better compete with small plants for limiting resources and may also have a greater capacity to withstand stress. We asked how size-dependent density, species density, recruitment and mortality varied between seasons and successional stages in a SDTF. We monitored a chronosequence in Yucatan, Mexico, over six years in three 0.1 ha plots in each of three successional stages: early (3–5 years-old), intermediate (18–20 years-old) and advanced (>50 years-old). Recruitment, mortality and species gain and loss rates were calculated from wet and dry season censuses separately for large (diameter > 5 cm) and small (1–5 cm in diameter) plants. We used linear mixed-effects models to assess the effects of successional stage, seasonality and their changes through time on demographic rates and on plant and species density. Seasonality affected demographic rates and density of large plants, which exhibited high wet-season recruitment and species gain rates at the early stage and high wet-season mortality at the intermediate stage, resulting in an increase in plant and species density early in succession followed by a subsequent stabilization. Small plant density decreased steadily after only 5 years of land abandonment, whereas species density increased with successional stage. A decline in species dominance may be responsible for these contrasting patterns. Seasonality, successional stage and their changes through time had a stronger influence on large plants, likely because of large among-plot variation of small plants. Notwithstanding the short duration of our study, our results suggest that climate-change driven decreases in rainy season precipitation may have an influence on successional dynamics in our study forest as strong as, or even stronger than, prolonged or severe droughts during the dry season.

Download Full-text

Fatty Acid Derived Compounds – the Dominant Volatile Class of the Essential Oil Poor Sonchus Arvensis Subsp. Uliginosus (Bieb.) Nyman

Natural Product Communications ◽

10.1177/1934578x0900400318 ◽

2009 ◽

Vol 4 (3) ◽

pp. 1934578X0900400 ◽

Cited By ~ 2

Author(s):

Niko Radulović ◽

Polina Blagojević ◽

Radosav Palić

Keyword(s):

Fatty Acid ◽

Essential Oil ◽

Green Leaf Volatiles ◽

Lower Percentage ◽

Multivariate Statistical ◽

Leaf Volatiles ◽

Aerial Parts ◽

Wide Range ◽

Sonchus Arvensis ◽

Total Oil

Chemical composition of the essential oil hydrodistilled from aerial parts of Sonchus arvensis subsp. uliginosus is reported for the first time. GC and GC-MS analyses of the oil enabled the identification of 114 components that represented 97.4% of the total oil. Main identified constituents were heneicosane (28.4%), ( Z)-3-hexen-1-ol (19.0%), ( E)-2-hexen-1-ol (11.6%), 1-eicosanol (7.5%) and tricosane (5.3%). Fatty acid derived compounds (“green leaf” volatiles, alkanes, n-alkenes, n-aldehydes and n-alcohols) were by far predominant (89.4%). A much lower percentage of shikimate metabolites (5.0%), carotenoid-derived compounds (1.7%) and terpenoids (0.9%) has also been detected in the oil. Compositions of the essential oils of S. arvensis subsp. uliginosus and other 18 randomly chosen species, characterized by a wide range of essential oil yields, belonging to different plant genera, were compared using multivariate statistical analysis. The results strongly suggest that the main volatiles of essential oil poor species (yields less then 0.1%) are fatty acid- and carotenoid derived compounds, while essential oil rich taxa (essential oil yields much higher then 0.1%) are generally characterized by the specific production of mono- and sesquiterpenoids, and/or phenylpropanoids.

Download Full-text

Smell of green leaf volatiles attracts white storks to freshly cut meadows

Scientific Reports ◽

10.1038/s41598-021-92073-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Martin Wikelski ◽

Michael Quetting ◽

Yachang Cheng ◽

Wolfgang Fiedler ◽

Andrea Flack ◽

...

Keyword(s):

Green Leaf Volatiles ◽

Food Sources ◽

Green Leaf ◽

Green Leaf Volatile ◽

Long Distance ◽

Novel Food ◽

Leaf Volatiles ◽

Olfactory Information ◽

Volatile Organic ◽

White Storks

AbstractFinding food is perhaps the most important task for all animals. Birds often show up unexpectedly at novel food sources such as freshly tilled fields or mown meadows. Here we test whether wild European white storks primarily use visual, social, auditory or olfactory information to find freshly cut farm pastures where insects and rodents abound. Aerial observations of an entire local stork population documented that birds could not have become aware of a mown field through auditory, visual or social information. Only birds within a 75° downwind cone over 0.4–16.6 km approached any mown field. Placing freshly cut grass from elsewhere on selected unmown fields elicited similarly immediate stork approaches. Furthermore, uncut fields that were sprayed with a green leaf volatile organic compound mix ((Z)-3-hexenal, (Z)-3-hexenol, hexenyl acetate), the smell of freshly cut grass, immediately attracted storks. The use of long-distance olfactory information for finding food may be common in birds, contrary to current perception.

Download Full-text