The importance of fieldwork

White-fronted Ground Tyrant (Muscisaxicola albifrons) with crane fly larvae and adults

Since first visiting Quelccaya in 2003, the objective of our work has been to accurately establish the summit climate, and quantitatively document how climate is recorded by the glacier - illuminating what we can learn about climate from ice cores. These efforts are documented in publications, with more still in preparation.

Working at high elevation on the glacier requires a bit of physical exertion (e.g., digging snowpits, wrestling with AWS tower extensions), as well as mental concentration (e.g., electrical wiring, datalogger programming). In spite of these requirements - or perhaps due to them - we also spend time at Quelccaya simply making observations, of both abiotic and biotic features and processes. These 'distractions' were often fascinating, including ice caves, streamflow and sediment transport, atmospheric convection, and abundant wildlife.

Our avian observations revealed behaviors previously unknown, some of which we have published (see here, here, and here), while others remain only partially understood. Another observation remained only in notes and photographs until recently, involving a fly. Since 2004, we encountered a large fly species at the AWS, typically clustered beneath the snow surface in proximity to the tower tubing and buried instrument enclosures. During transition-season visits in April and October 2014, we observed the flies on the snow surface at our moraine camp (5,200 m), crawling around in our tents, and being eaten by birds.

We posted photographs of this fly species on iNaturalist, where it remained unidentified for five years. In November, Russian entomologist Dmitry Gavryushin observed the report and took interest. He was able to identify the crane fly to species, based on a speciman from Bolivia described by prominent crane fly taxonomist Charles P. Alexander, who was affiliated with the UMass Entomology Department from 1922-1959. The coincidences continue, for the type locality for Dicranomyia (Dicranomyia) perexcelsior (Alexander) is Chacaltaya Glacier in the Cordillera Real of Bolivia. This is where Niethammer (1953) first described an association between Andean glaciers and our "Glacier Bird" (White-winged Diuca Finch; Idiopsar speculifera).

Our Quelccaya crane flies are the highest-elevation observations from anywhere in the world, which came to the attention of Pjotr Oosterbroek at the Naturalis Biodiversity Center in The Netherlands. Pjotr's enthusiasm and initiative drew in Christophe Dufour from the Muséum d’histoire naturelle in Neuchâtel, Switzerland, and resulted in our latest publication, on high-elevation crane flies. Working with these two was an absolute pleasure.

Our experience at Quelccaya demonstrates that casual observations from seldom-visited, extreme environments are often invaluable. When making them outside of one's field of expertise, one can never know just how important they might be. This is especially true during the rapid environmental changes underway. Chacaltaya Glacier, for example, no longer exists; no one will ever again observe crane flies or Glacier Birds there. Sadly, this will likely also be the case at Quelccaya before the end of the century (Yarleque et al., 2018).

 

Update (with Cranefly news)

Our AWS on Quelccaya has been decommissioned, and everything except deeply-buried tower tubing has been removed. Meteorological measurements spanning 2003 to 2018 are currently being analyzed; we welcome collaboration and data-sharing inquiries.

At least one aspect of our glacier field research will continue for another year. Also, we aspire to investigate the impact of continuing glacier recession on avian activity at Quelccaya (as reported here and here).

This week we learned more about a particular insect that was typically found at the AWS each time we visited for service and data recovery. Individuals and clusters of craneflies were observed beneath the snow surface in association with the AWS tower tubes (see above and below photos). We also observed craneflies on the snow surface near the AWS, elsewhere on the glacier, and at our glacier-margin camp. Craneflies appear to be an important food source for the many high-elevation bird species in the Quelccaya area (> 5,000m).

Cranefly photos were posted to iNaturalist after fieldwork in April 2014, seeking identification. These were identified this summer - after 6 years - based on a single specimen from Chacaltaya in Bolivia. Interestingly, this is the same location where the "Glacier Bird" (White-winged Diuca Finch, Idiopsar speculifera) was first observed in association with glaciers; Chacaltaya no longer exists.

The Quelccaya cranefly species is Dicranomyia hirsutissima. According to Pjotr Oosterbroek, author of "Catalogue of the Craneflies of the World", this is the highest known Cranefly record for all 15,000+ species found throughout the world.

This is yet another fascinating discovery from Quelccaya and the Cordillera Vilcanota, during nearly 50 years of investigation begun by Ohio State University scientists John Mercer and Lonnie Thompson.

Quelccaya Images

A new index (of sorts) has been compiled to better organize Quelccaya images depicting the weather station, snowpit measurements and sampling, as well as other aspects of fieldwork:  Quelccaya Gallery.

Links to images of birds living and nesting around & on the glacier are here.

New paper: birds & glaciers at Quelccaya

Important scientific information has been emerging from research at Quelccaya Ice Cap for nearly 50 years, from ice core records, glacial geology studies, and meteorological measurements. In recent years, research has also yielded new biological findings, revealing the importance of glaciers to the lives of birds in the High Andes.

We published a paper in 2008 documenting nesting on glacier ice at Quelccaya by White-winged Diuca-Finches. Diucas are a medium-size tanager species found in the High Andes of Peru, Bolivia, and Chile, and prior to our new publication were the only bird known to routinely build nests directly on glacier ice. This species is also among the highest-elevation nesting species in the world – to at least 5400 meters (18,000 feet) – despite an environment with average temperatures below freezing, high winds, frequent snowfall, and intense solar radiation.

Our paper in the latest Wilson Journal of Ornithology provides new details on this unique behavior. Ten years of additional observations include fieldwork at Quelccaya outside the core dry season, culminating in 2 weeks at the glacier in 2016 filming a Diuca nest with 2 chicks. Besides observations of multiple active nests, the paper also documents glacier nesting by another species, the White-fronted Ground-Tyrant, and describes nocturnal roosting within or under a glacier by 5 different species. The publication includes an online Supplement (also available here) containing additional images, and links to the BBC/PBS film.

Nesting and roosting on glaciers are adaptations to the harsh environment at high elevations in the Andes, as cavities within the ice provide both a protected microclimate and protection from predators. Are glaciers important to other species, elsewhere? What happens when the glaciers are gone, victims of climate change?

Andean glaciers are shrinking rapidly, and even the largest are likely to disappear this century. Although undocumented until only 10 years ago, the lives of several bird species appear to be dependent upon these glaciers. Their loss may have a direct, negative effect on biodiversity of the High Andes - in addition to other impacts, such as water resources.

Seasonal change

The second half of September at Quelccaya is typically characterized by increasing snowfall, as the dry season concludes. Cloudiness increases rapidly at this time of year, as evidenced and measured by sharply increasing longwave radiation receipt. Air temperature continues a steady increase into November.

These aspects of Quelccaya climate are illustrated by the 2 images below, acquired by Senitinel-2 only 5 days apart. On 27 September (upper image), fresh snow is evident at higher elevations of the Vilcanota, particularly on glaciers and eastern portions of this scene. By 2 October (through high thin clouds), fresh snow had ablated from the landscape (middle image). Lower elevations of Quelccaya Ice Cap also become snow-free, revealing the transient snowline (also see lower image).

Further evidence of this seasonal change in climate is provided by the lower image - an enlargement of yesterday's image - showing the apparent disappearance of ice cover from a marginal lake (circled). In July this ice was thick enough to support a person walking across the lake.

 

Return from fieldwork, forthcoming papers [updated]

August fieldwork was successful and fun, despite rather unstable weather. Considerable dry-season snow blanketed south-facing slopes and the entire glacier, yet little new snow occurred during our ~10 days at Quelccaya. The panorama above shows Boulder Lake and one lobe of the glacier where we have conducted observations since 2003; Lonnie Thompson has worked here since 1974. More photos and details of recent fieldwork will be posted in the next week or two.

A variety of new papers will soon be available, so look for links on this website. As indicated below, some are closer to publication than others...

[UPDATE 10/16] Yarleque, C., M. Vuille, D.R. Hardy, O.E. Timm, J. De la Cruz, H. Ramos, and A. Rabatel. Projections of the future disappearance of the Quelccaya Ice Cap in the Central Andes. 2018. Scientific Reports. To be freely available on 22 October from Nature!

Hardy, S.P., D.R. Hardy, and K. Castañeda Gil. Avian nesting and roosting on glaciers at high elevation, Cordillera Vilcanota, Peru. Accepted 20 Aug. for Wilson Journal of Ornithology.

Hurley, J.V., M. Vuille, and D.R. Hardy. On the interpretation of the ENSO signal embedded in the stable isotopic composition of Quelccaya Ice Cap, Peru. Submitted to JGR-Atmospheres.

Yarleque, C., M. Vuille, D.R. Hardy, O.E. Timm, and H. Ramos, Future projections of precipitation variability over the eastern Central Andes. Submitted to Frontiers.

Chadwell, C.D., D.R. Hardy, C. Braun, and H.H. Brecher. Thinning of the Quelccaya Ice Cap over the last thirty years. In revision/reorganization.

Hardy, D.R., R.S. Bradley, et al. The summit climate of Quelccaya Ice Cap. In preparation.

More snow this week

As forecast by SENAMHI, the Vilcanota has received more snow. The Sentinel-2 image from yesterday shows snowcover surrounding Sibinacocha, as well as the area around the hamlet of Phinaya.

weather forecast: more of the same

The weather forecast for today and tomorrow from SENAMHI calls for rain and snow of moderate to strong intensity in the mountains, with hail expected above 3,000 m; wind gusts to 45 km/hr.

Quelccaya's location here is indicated by the red circle. "Danger Level 3"

And it appears the forecast was accurate, with restricted travel...

#TVPerúInforma

August begins snowy

Sentinel-2 acquired an image of the Cordillera Vilcanota yesterday, 11 days since their previously-published image (via EO Browser)... and fresh snowcover is still widespread.

Compare these two identical scenes, from 3 August (upper) and the last time snowcover was restricted to the highest elevations, on 30 May (lower) - two months ago!

The community of Phinaya, where many alpaca and llama herders are based, is located within the red circle. During June and July, snowcover appears to have been only occasional at this elevation. The smaller red hexagon is the Quelccaya weather station location (5,680 m), illustrating that the transient snowline has remained below the glacier margin (approx. 5,300 m) since May.

Fieldwork begins in a week!

¡Tanta nieve! So much snow! [updated x2]

The snowy dry season of 2018 continues in the Cordillera Vilcanota. Yesterday's Sentinel-2 image (above) reveals a landscape blanketed by snow above 4500-4700 m. Quelccaya Ice Cap (lower right) is difficult to delineate, suggesting substantial accumulation at the margin. Hopefully our instrumentation continues to record hourly snowfall at the summit.

Note the variation in color of lakes just west of the glacier, surrounding the area of our camp (labeled). This reflects varying suspended sediment input, with relatively high concentrations apparently flowing into the Qori Kalis proglacial lake (north of camp); snow is accumulating, while also melting and delivering sediment to the lakes. The 'double' lake to the northwest of camp (and Sibinacocha) appear dark blue, as upstream wetlands (bofedales) filter sediment from freshly-exposed areas proximal to the glaciers.

We will be in the area during the second half of August, measuring snow and recovering weather station data. Fieldwork will occur later than normal, allowing an assessment of what appears to be an anomalous year. Although this snow will be beneficial to glacier mass balance, the toll on camelids (llama, alpaca) could be severe - without warming solar radiation typical of the dry season.

[UPDATE 7/26: A press release from SENAMHI* earlier this week (23 July) describes snowfall in the preceding 72 hours above 3,800 m in the Andes, accumulating to 20 cm. In conjunction with clouds, they warn of low temperatures and prolonged snowcover reducing food for livestock.

Gustavo Valdivia wrote yesterday learning details of the situation in the Cordillera Vilcanota. He received a call from the Phinaya community president, who described the situation as critical, because a lot of alpacas died in recent days. The local people agree that the weather is very unusual.

Press releases from SENAMHI can be found here (in Spanish), with a machine translation  here. 

*SENAMHI is The National Meteorology and Hydrology Service of Peru or El Servicio Nacional de Meteorología e Hidrología del Perú]

[UPDATE 7/27:  Today I learned from Bronwen Konecky (Washington University) that SENAMHI is making daily meteorological summaries available on their website. The closest station to Quelccaya - and one of their highest - is Sibinacocha, at ~4890 m (labeled on map above). These data show 11 mm of water equivalent precipitation on 21 July, followed by 5.9 on the 22nd. Since this automated station is located at the southern end of the lake, the image above suggests that considerably more snow fell at higher elevations. The regional nature of this event is demonstrated by daily totals from Sicuani (~3600 m, 45 km to the SW); very similar daily totals were recorded.

To access any SENAMHI data in Peru, go here, then use the "Seleccionar" button to select a District; zoom in on the map. Thanks, SENAMHI.]

BBC Glacier Bird filming

During our April/May 2016 fieldwork, we were joined by a BBC Natural History Unit crew. Their objective was to film White-winged Diuca Finches nesting on the glacier, a breeding behavior unknown among all other bird species. The project timing was fraught with uncertainty, for only 2 other active Diuca nests had ever been observed, and the 2015-16 El Niño event considerably impacted Quelccaya climate (overview here of a manuscript now out for review). Foremost in our minds was whether we could find active nests to film, when we arrived in April.

Fortunately, our timing was perfect; we observed all stages of breeding behavior, and successfully installed a remote camera at one of the nest sites. After a year in production the segment aired on BBC as part of an episode on the Andes, in the series Mountain: Life at the Extreme. Links to the BBC series are here and here.

This month, BBC Glacier Bird footage will premiere in the United States on PBS. The series takes a new name, Kingdoms of the Sky, with a new presenter, but otherwise appears identical: a three-part documentary "revealing the extraordinary animals and remarkable people who make a home on the iconic mountain ranges of the world - Rockies, Himalaya and Andes." The three episodes will initially air on Wednesday evenings, beginning with The Rockies on July 11 at 9 PM EDT. Himalaya premieres one week later on July 18, and Andes premieres on July 25.

The PBS series website is here, and DVDs can be pre-ordered now.

At the moment, the Glacier Bird segment can be viewed from the right-hand side of the series homepage. Click on "Meet the Bird that Nests Inside Glaciers" to see the first-ever footage of Diuca speculifera nestlings.

Even better is an 8-minute, behind-the-scenes look at Quelccaya filming, available from PBS here. Images from that clip are included above and below.

Our extended fieldwork with BBC in April 2016 was good fun, and provided new observations of Diuca and other high-elevation species. Please check our website for the Glacier Bird, and stay tuned for a new publication (still in review; contact us for a synopsis of the paper, or a pre-print).

Snowcover update & ice retreat

Quelccaya Ice Cap currently remains largely blanketed by snowcover, excepting the very lowest ablation zone (e.g., Qori Kalis outlet glacier). The GIF above contains only 2 images; the snowy scene without red annotation was acquired last week (10 May 2018). Contrast 2018 snowcover on the glacier with that 2 years earlier, at the end of March 2016.

These images show a portion of the ice cap's western margin. We have visited this area at least annually since 2003, witnessing continuous retreat of the margin and changes in all of these proglacial lakes.

The red ellipses on the 2016 image highlight two areas where margin retreat is clearly evident. Our GPS measurements up through 2017 at the lower section indicate a retreat rate of 10-15 m/year. At the small red circle by the larger lake, the area of bedrock near the circle has expanded, and only a small portion of the glacier still extends into the lake (contrast 2013). Throughout our years of fieldwork in the area we have observed ice calving into this lake, which began forming in ~1985 (Thompson et al., 2013). Within the next year or two the glacier will no longer reach the lake.

One consequence of Quelccaya margin retreat and thinning is loss of suitable nest sites for the "Andean Glacier Bird" (White-winged Diuca-Finch, Idiopsar speculifer; formerly Diuca speculifera). Until the mid-2000s the area near the lower ellipse supported a relatively high density of nests, built directly on the ice (Hardy and Hardy, 2008 and here). As ice at this margin thinned and became less steep, the area was abandoned for nesting. More recently, the area near the small circle has been used for nesting (e.g., 2014 oblique photo of margin at the lake), but as the ice becomes thinner the birds will need to move up in elevation to find suitable, steep ice slopes. Furthermore, the Glacier Bird is not the only bird species impacted by ice recession; a new manuscript detailing this is currently in review (and available upon request). 

Ref:  Thompson, L.G., E. Mosley-Thompson, M.E. Davis, V.S. Zagorodnov, I.M. Howat, V.N. Mikhalenko, and P.-N. Lin. 2013. Annually resolved ice core records of tropical climate variability over the past ~1800 years. Science, vol. 340, 945-950. 10.1126/science.1234210

Glacier Bird on BBC

The final episode of BBC TWO's new documentary series about mountains will air at 9 pm on 13 September, featuring a variety of sequences filmed in the Andes.

Among the Andes sequences will be a segment filmed at Quelccaya, as described above. Several wonderful "behind the scenes" clips have been produced for the Glacier Bird film, one of which is here (hopefully available soon in North America). A link to the page above, with an embedded clip, is here.

Since the time of filming - just last year - science has moved forward:  we have discovered a second species of bird which also nests on the glacier (Hardy et al., submitted to Wilson Journal of Ornithology), and Glacier Bird's taxonomic classification has changed from Diuca speculifera to Idiopsar speculifer. The common name in English remains White-winged Diuca-Finch, but this too may change because the bird is not a Diuca-Finch!

For those not in the UK, the series will be broadcast in North America by PBS at a later date.

"Mountain: Life At The Extreme" (new BBC series)

On Wednesday evenings at 9 pm starting 30 August, television network BBC TWO will be airing a new 3-part documentary series exploring three different mountain ranges: the Rockies, the Himalaya and the Andes.

Each episode is more than a natural history program in that it depicts examples of both the "extraordinary animals and remarkable people" living in these extreme environments (quote credit here).

The Rocky Mountain sequences feature wolverines, extreme skier Hilaree O'Neill, big horn sheep, and Native American horse racing - among others. Clips and more are available on their website:  <http://www.bbc.co.uk/programmes/b093x4gb>

The Himalaya episode also features animals, along with the people comprising remarkable ancient cultures. One exciting sequence follows Nepali ultrarunner Mira Rai through a race. (Mira is featured in the May 2017 issue of Outside Magazine, and will be running one of the UTMB races in Chamonix this week.) For more on the episode, including clips and updated information, check the BBC website: <http://www.bbc.co.uk/programmes/b094klt5>

Details on the final episode airing 13 September have not yet being released. This post will be updated when they are - for it includes a sequence on our work at Quelccaya.

Unfortunately for North Americans, BBC TWO is not available. There will be rebroadcasts by PBS, but dates are not yet available.

dry-season weather

We visited Quelccaya for fieldwork during July this year and experienced a long interval of sunny, dry weather. Although July is solidly within the core winter dry season, the atmosphere was particularly dry at this time; the cloud visible in the background above was literally the largest we saw during our time at the ice cap.

Below are two oblique views of the glacier margin, on the day that we arrived in the area (20 July) and the day we departed (27 July). Due to funding constraints, this was a relatively short trip. After 8 days of clear sky and intense solar radiation, some might expect to see more change in the transient snowline than the images show. In other years of fieldwork this has certainly been the case. This year, the areas of greatest apparent change over the interval are highlighted by the red ellipses. Although these areas were determined subjectively from the images, rather than measurements of snow depth, two clear-sky satellite images roughly bracketing the period reveal a similar pattern (see below).

Why so little ablation of snow, within a zone which is both thinning and retreating rapidly in recent decades? Most likely, this was due to the combination of dry atmosphere and low wind speed during this interval. With a negative vapor pressure gradient due to the dry air, any available energy went toward sublimation, requiring ~8 times more energy per kilogram than melting. Furthermore, low wind speed suppressed turbulent transfer of latent heat. At the summit, relative humidity was typically ~10 percent (vapor pressure <2 hPa) and rarely rising to 50 percent during the afternoons.

Despite little ablation during this brief interval of the dry season, recession of the ice cap in this area is accelerating. A subsequent post and paper will quantify retreat we have been measuring since 2008, revealing the profound changes associated with the 2015-16 El Niño event.

Seasonality of accumulation and ablation: not simple!

Earlier posts here have discussed how snow accumulation at Quelccaya during the 2015-16 El Niño was considerably below normal. We verified AWS measurements during April and May fieldwork, measuring for example a mere 30 cm of snow at an elevation only 130 m below the ice cap's summit! On top, we made comprehensive measurements and obtained snow samples for frozen transport and analyses which are currently underway. However, preservation of this meager accumulation will depend upon the extent of both precipitation and ablation currently occurring -- during the 2016 dry season (i.e., approx. June - October).

The following sequence of Landsat 8 images were obtained from the USGS, corresponding to dates shown in pink/purple on the following timeseries of snow surface height at the summit of Quelccaya. Height increases are primarily the result of snowfall, while decreases mostly reflect melting.  In viewing the images below, it might be helpful to have this graph open in another tab or window; click here for a jpeg or here for a PDF.

A composite GIF of the images is shown first. For more detail on each image, scroll down. Captions for each relate snowcover in the scene to AWS measurements in the days and months prior. We will continue tracking accumulation at the summit and relating surface height to Landsat imagery as the season continues. Further information about accumulation in past years, and interpretation of AWS measurements, is detailed in our comprehensive paper in the Journal of Geophysical Research (Hurley et al., 2015). See our previous blog post for images of fieldwork during April and May.
 

Fig. 1 - Snow-covered glacier and snowy landscape (5 Feb.), after one of the final snowfall events of the 2015-16 "core" wet season. Although impossible to assess the depth of accumulation from this visual image, note high albedo of the entire glacier, raising the reflectivity of incoming shortwave radiation (solar).

Fig. 2 - Two weeks later (21 Feb.), glacier ice is becoming exposed around the margin, and snow has melted from the surrounding landscape. Most of the glacier remains bright (i.e., high albedo) due to a minor snowfall event several days prior (see graph above). The wet season continues through February, and as in figure 1, clouds are indicative of atmospheric instability.

Fig. 3 - During the month between this image (24 Mar.) and that in figure 2, a net lowering of glacier surface height occurred, despite a snowy interval (late Feb.) and a large snowfall event in early March. A larger area of glacier ice is visible around the margin, and albedo has decreased at all but the highest elevations. To the west of the ice cap a solid red circle indicates the location of our camp during April / May fieldwork.

Fig. 4 - Only slight changes in the month since figure 3. On this date (25 Apr.) we were at the glacier, camped at the location indicated in figure 3. Just 5 days prior, a precipitation event with heavy graupel was sufficient to collapse one of our tents. Snowcover blanketed the regional landscape far to the west the next morning; four days later (see above), new snow remains on the glacier but has melted from the landscape. Note location of AWS, which is not indicated on subsequent figures.

Fig. 5 - During our time at Quelccaya we observed a seasonal change in weather which we interpret to be the transition from wet to dry seasons. Between a few days prior to the time of figure 4 and our departure on 4 May, the atmosphere became considerably more stable. Particularly at lower elevations on the ice cap, the melt rate was tremendous, and with a thin cover of snow the transient snowline rapidly increased in elevation. This image from 11 May - only 2 weeks after that in figure 4 - demonstrates how rapidly mass can be lost from a glacier in years of low accumulation.

Fig. 6 - Rapid ablation earlier in the month was halted by a relatively minor amount of accumulation ending just a few days prior to this image (27 May). The receipt of net radiation decreased tremendously due to higher albedo of the fresh snowcover.

Fig. 7 - Two weeks later (12 Jun.) mid-May snow accumulation is ablating. Due to a problem processing telemetry data, snowfall in the days just prior to and following this date is not known.

Fig. 8 - This image of the same scene from 28 Jun. depicts a typical dry-season snowfall event which occurred the day before. This is the southern hemisphere winter, when air temperatures are lower and precipitation arrives in the form of snow at lower elevations than during the wet season. Although partially obscured by clouds, note widespread snowcover on the landscape.

Fig. 9 - Two weeks after Fig. 8, snow lingers on the landscape, yet albedo is decreasing at lower elevations of the glacier as the new snow melts and sublimates. Ultimately, the extent to which 2015-16 accumulation is preserved will depend upon whether additional winter events occur. In general, however, surface lowering at the summit (i.e., ablation) typically - but not always - accelerates during August into September, and sometimes into October. Net accumulation for the mass-balance year cannot be determined until the subsequent wet season begins.

Fieldwork at Quelccaya, April-May 2016

We returned recently from an exciting 19 days of fieldwork at Quelccaya. The expedition was timed to coincide with the conclusion of the wet season following the very strong 2015-16 El Niño, and we gained considerable new information. Specific objectives related to this anomalous year included:  AWS data recovery and annual instrument maintenance; snowpit measurements and sampling for chemical analyses; and both GPS mass balance and ice margin measurements. We also had an opportunity - which for over a decade was only a dream - to spend time learning about and documenting breeding behavior of the White-winged Diuca-Finch. This species is among the highest-elevation nesting birds of the Western Hemisphere, and is the only species known to build nests on glaciers (see here for background, soon to be updated); our recent observations yielded a wealth of new understandings. As always, Vicencio Expeditions provided fantastic logistical support, allowing our team of 5 to work safely and efficiently. Below is a quick collection of images documenting some of our observations.

Fig. 1 (above):  Quelccaya Ice Cap's western margin, at which our group spent 2+ weeks during April and early May. Note that the transient snowline is already at nearly 5500 m, due to low accumulation and warmth during the strong 2015-16 El Niño. Qori Kalis outlet glacier is partially visible towards the left side of the image; our efforts on this trip were concentrated at the outlet glacier just right of center.

Fig. 2:  Alipampa Camp at the end of the road (4765 m), where we spent 2 nights acclimatizing. Snowfall overnight was somewhat unexpected.

Fig. 3:  More snow, three mornings later, at Moraine Camp (~5200 m). Note frozen lake, as well as people and horse for scale.

Fig. 4:  Quelccaya margin just south of the figure 1 panorama. Tiny patches of new snow are visible on the otherwise-dark ablation zone of the lower ice tongue. This low-albedo surface absorbs roughly half of the solar radiation incident upon it on sunny days, becoming a maze of tiny meltwater runoff channels.

Fig. 5:  Qori Kalis outlet glacier, which has thinned dramatically in recent years - yet still extends into the lake.

Fig. 6:  Mountain Guide Benjamin Felix Vicencio gets an overview of Qori Kalis.

Fig. 7:  After several snowy days initially, high pressure built in over Quelccaya, resulting in extensive melting at all elevations on the glacier. Meltwater production led to hours of repeated calving at this ice face, filling part of the lake with ice fragments.

Fig. 8:  Meltwater runoff from the ice margin (above rocks in this view) brought greater discharge to many streams than we had seen previously.

Fig. 9:  Evidence from one of the runoff channels of high discharge during the wet season; these are roots from a plant which had become established near the stream.

Fig. 10:  At the summit AWS, Felix is always eager to help. For the past 12 years, the station's enclosures have been buried upon our dry-season arrival. During the current El Niño event, accumulation was much lower than normal. Indeed, at the end of April - with potentially 6-7 months of ablation ahead before the next wet season - accumulation (w.e.) was less than any other year of the 2003 ice core record since at least the late-19th century*! We will soon provide more details of this extreme situation.

[*Caveats to this statement are required. Current accumulation is based on the amount present on 2 May 2016, above the 2015 dry season surface (water equivalence). This may under-estimate accumulation if a greater-than-normal proportion of precipitation was in the form of rain and percolated completely through the annual increment. Under-estimation could also occur if a greater proportion of meltwater percolated completely through, rather than refreezing within 2015-16 accumulation. However, the accumulation present in early May has always been less than that preserved when the subsequent wet season begins (due, for example, to dry-season sublimation).]

Fig. 11:  The outlet glacier just above our camp, where a major focus of the most-recent expedition was to study the breeding of Diuca speculifera or White-winged Diuca-Finch - the "Glacier Bird of the Andes".

Fig. 12:  Four intensive days were spent searching for active nests, which diucas build directly on glacier ice in well-protected, hidden locations (earlier, initial details here).

Fig. 13:  Locating active nests of any bird species requires patience and astute observation skills. Extra motivation is required to do so in the snow at elevations above 5000 meters.

Fig. 14:  Two key members of the nest-searching team. All bird observations throughout the entire expedition are available in eBird (~50 spp. from >4800 m).

Fig. 15:  An adult Diuca speculifera seeking insects on floating ice fragments (see lake in figs 7 & 11).

Fig. 16:  At the site of one diuca nest, high on a 60-meter cliff face. Ideally - as in this case - the birds choose nest sites which are safe from predation (esp. Fox, Pseudalopex culpaeus and Mountain Caracara, Phalcoboenus megalopterus) and offer thermal protection (esp. heat loss by longwave radiation). The actual nest site here is ~2 m to the right of the person.

Fig. 17:  A juvenile diuca begging for food from a parent.

Fig. 18:  Tremendous biodiversity exists in Cordillera Vilcanota. Here a lizard basks in the sun adjacent to glacier ice (background), an atypical environment for most lizard species.

Fig. 19:  Quelccaya margin just south of the section we concentrated on this time. A decade ago this margin was also a steep cliff, with numerous diuca nests every year. However, over the past 30 years our measurements with Dave Chadwell (Scripps & UCSD) document that the glacier in this area has thinned by more than 60 meters (paper in review). Where will diucas nest in the future, as recession of the ice cap accelerates and suitable locations disappear?

Fig. 20:  Sunrise on Nevado Ausangate, highest peak of the Cordillera Vilcanota (6384 m).