Pituffik/Thule Area, north­west Greenland

Pere­grine Fal­con and Gyr­fal­con Monitoring

His­tory, objec­tives, and pre­vi­ous results of project:  Sys­tem­atic sur­veys for nest­ing Pere­grine Fal­cons and Gyr­fal­cons have occurred in the Thule area every year since 1993, with our pri­mary study area of approx­i­mately 750 km of coast­line being estab­lished in 2001. Each year this coast­line is sur­veyed for breed­ing and non-breeding fal­cons. At loca­tions where nest­ing is observed, data are recorded on repro­duc­tion, nest­ing chronol­ogy, and nest site char­ac­ter­is­tics. When pos­si­ble, chicks are banded and sam­pled and molted feath­ers, egg shell frag­ments, and prey remains are col­lected, all to be used in other projects (e.g., adult turnover stud­ies, pol­lu­tant analy­sis, sta­ble iso­topes, genetics).

Pre­vi­ous results from this project include the doc­u­men­ta­tion of a recently estab­lished and increas­ing pop­u­la­tion of Pere­grines, and the first-ever long-term stud­ies on High Arc­tic pop­u­la­tions of both Pere­grines and Gyr­fal­cons.  High­lights from the Gyr­fal­con research include a sig­nif­i­cant advance­ment of lay date from 1993 to cur­rent (nest­ing ear­lier, likely asso­ci­ated with chang­ing envi­ron­ment) in addi­tion to the first-ever infor­ma­tion on diet and repro­duc­tion for a High Arc­tic population.    

Results from 2019:  In our pri­mary study area all 18 known Pere­grine Fal­con nest sites were sur­veyed and 15 out of 20 (75%) of known Gyr­fal­con nest sites were sur­veyed for occu­pancy. Pairs of Pere­grines were observed at 9 of the 18 sur­veyed loca­tions (50%) while pairs of Gyr­fal­cons were observed at 7 of the 16 sur­veyed loca­tions (44%). No new nests were found. This marks the sec­ond con­sec­u­tive sea­son the num­ber of occu­pied Pere­grine nests has declined, pos­si­bly a carry-over effect of the extremely cold and wet sum­mer in 2018. Of par­tic­u­lar inter­est, sev­eral nests which have had Pere­grines for three or more con­sec­u­tive years were vacant.  

Objec­tives for 2020:  Sur­vey all the coast­line and inland cliffs from 76.00°N to 77.0°N for Pere­grine Fal­cons and Gyr­fal­cons. At occu­pied cliffs, deter­mine if fal­cons are breed­ing and if yes, empha­sis will be placed on installing nest cam­eras (see below) when possible.  



Peregrine Falcon chicks at the most northern known Peregrine nest in the world.

Adult female pere­grine and chicks. Pere­grine fal­con chicks at the most north­ern known Pere­grine nest in the world. 


Pere­grine and Gyr­fal­con Nest Cam­era Study

His­tory, objec­tives, and pre­vi­ous results of project:  We are work­ing on mul­ti­ple col­lab­o­ra­tive research projects with col­leagues study­ing fal­cons in other parts of the Arc­tic and it has become clear that we need to col­lect bet­ter infor­ma­tion on annual repro­duc­tion and nest­ing chronol­ogy. Sur­veys for breed­ing fal­cons in north­west Green­land occur from late June through early August. Dur­ing this period, Gyr­fal­con young are usu­ally at a min­i­mum half grown, and in many instances have departed the nest by mid-to-late July. Pere­grines nest about one month later, and young fre­quently don’t hatch until mid-July at the ear­li­est. In many instances our nest vis­its result in us find­ing pairs of Pere­grines incu­bat­ing eggs or brood­ing small young and Gyr­fal­con young that have already fledged. These sce­nar­ios pro­vide us very lit­tle infor­ma­tion on repro­duc­tion (and nest­ing chronol­ogy, since we don’t know when the eggs hatched), since not all eggs hatch and fre­quently a por­tion of young die before ever depart­ing the nest.

In hopes of increas­ing our knowl­edge on fal­con repro­duc­tion in the Thule area, dur­ing the 2017 field sea­son we began installing nest cam­eras at both Pere­grine Fal­con and Gyr­fal­con nests. This allowed us to effec­tively increase the length of our field sea­son with­out need­ing to have a team in Green­land for mul­ti­ple addi­tional months. In 2017 we took the approach of installing two types of cam­eras in many nests, short-term cam­eras, with a life expectancy of only two-to-three months, and long-term cam­eras, with a life expectancy of 12 to 16 months.

Results from 2018 showed that two types of cam­eras were not needed, and that bat­tery life in the cold Arc­tic envi­ron­ment is much bet­ter than antic­i­pated. All cam­eras func­tioned through the breed­ing sea­son they were installed in until their removal the fol­low­ing sum­mer. This allowed us to col­lect data from when fal­cons first arrived at nests up until they departed for out­ward migra­tion. Addi­tion­ally, we had sur­pris­ing results dur­ing win­ter months, for exam­ple, ravens uti­liz­ing well pro­tected Gyr­fal­con nests for extended peri­ods of time. At cliffs where fal­cons moved nest ledges from 2018 to 2019 (and in one case as far back as 2017) we chose to install new cam­eras at active, new nest ledges, and to reuse old-yet-functioning cam­eras in unoc­cu­pied nest ledges. This way we will hope­fully still get excel­lent data should fal­con choose to move back to recently used nest ledges.  

Results from 2019:  Dur­ing the 2019 field sea­son we were able to retrieve cam­eras from nine dif­fer­ent Pere­grine nest­ing cliffs (includ­ing two installed in 2017 that we were unable to retrieve in 2018), to include mul­ti­ple cam­eras at two cliffs. All retrieved cam­eras were replaced with either new or reused cam­eras, and at all nine nest­ing cliffs all nest ledges occu­pied from 2017 onward now have active cam­eras. Cam­eras were retrieved and replaced at three Gyr­fal­con nest­ing cliffs.  

Gen­eral high­lights:
–at one Pere­grine cliff, which was unoc­cu­pied on mul­ti­ple vis­its, cam­era data showed a pair of Pere­grines actively work­ing the scrape early in the sea­son. No idea what hap­pened to the pair.
–sim­i­lar to 2018, a dark sil­ver female Gyr­fal­con vis­ited two nests unsuc­cess­fully look­ing for a mate, although both nests were later used by white pairs.
–at mul­ti­ple Pere­grine cliffs it showed pairs of Pere­grines deal­ing with snow (up to sev­eral inches) dur­ing both the incu­ba­tion and young rear­ing period dur­ing the 2018 sum­mer
–doc­u­mented one Pere­grine nest with eggs hatch­ing in early-August and the young sur­viv­ing until fledg­ing age. Pre­vi­ously, we con­sid­ered eggs that had not hatched by the end of July as dead or infertile.


A pair of white Gyr­fal­cons with recently hatched                                                   young.

Gyr­fal­con young being fed an Arc­tic Hare leveret.

An adult female Pere­grine Fal­con incu­bat­ing eggs after a snow storm.

An adult female Pere­grine feed­ing her young.


Objec­tives for 2020:  Re-visit all fal­con nests that had cam­eras installed in 2019 and col­lect cam­eras and data chips. Install new cam­eras in active nests and old-yet-functioning cam­eras in recently used nests. Install cam­eras at any addi­tional Pere­grine and Gyr­fal­con nests that are found and that are read­ily acces­si­ble. With the assis­tance of under­grad­u­ate stu­dents at Augus­tana Col­lege (IL), con­tinue pro­cess­ing all nest cam­era pho­tos col­lected to date to tab­u­late infor­ma­tion on nest­ing chronol­ogy, repro­duc­tion, prey, etc.


Arc­tic Tern Colony Surveys

His­tory, objec­tives, and pre­vi­ous results of study:  The Thule area is the north­ern limit of the Arc­tic Tern breed­ing range and over the past 15 years it appears that the rel­a­tively small pop­u­la­tion of terns in this area (150–250 pairs) has declined.  No his­toric data has ever been recorded on this pop­u­la­tion other than gen­eral esti­mates of colony size; how­ever, this was only based on the num­ber of indi­vid­ual birds observed fly­ing above colonies.  Start­ing in 2009 we began sys­tem­at­i­cally sur­vey­ing the seven known tern colonies (all on small islands) and all other suit­able nest­ing loca­tions along the 750 km of coast­line we sur­vey for nest­ing fal­cons.  When occu­pied colonies are found, we sys­tem­at­i­cally sur­vey the colonies and record infor­ma­tion on repro­duc­tion and breed­ing chronol­ogy (num­ber of nests, num­ber of eggs or chicks, age of young).  Using this infor­ma­tion, over the next 5–10 year period we hope to be able to deter­mine what changes are occur­ring in the pop­u­la­tion, be it a reduc­tion in the num­ber of pairs of terns or changes in nest­ing chronol­ogy (e.g., nest­ing ear­lier, a com­mon result of cli­mate change and a warm­ing High Arc­tic environment).

In 2017 we pub­lished a man­u­script that included all pre­vi­ously col­lected data on the tern pop­u­la­tion in north­west Green­land and com­pared it with our find­ings from 2009 to 2017. The key find­ings from the man­u­script showed a steady decline from approx­i­mately 250 pairs of Arc­tic Terns in the late 1960s to late 1980s to an aver­age of ~50 over the past nine years. Four pre­vi­ously iden­ti­fied colonies have been extir­pated while three cur­rent colonies have under­gone sig­nif­i­cant reduc­tions in size. In 2017 we found only 25 nests, the fewest to date, and con­tin­ues an appar­ent rapid decline in the num­ber of nest­ing pairs in our study area.

Results from 2019:  We vis­ited all pre­vi­ously known colonies and pos­si­ble nest­ing loca­tions and found Arc­tic Terns nest­ing at five dif­fer­ent loca­tions and present at a sixth. A total of 40 nests were found with 15 at one colony and an esti­mated 20 at another (chicks had begun to hatch so we were not able to sur­vey, num­ber based on adults in atten­dance). This is a sig­nif­i­cant improve­ment from the past few years, although still much lower than even 5 to 10 years ago.  

Objec­tives for 2020:  Con­tinue sur­vey­ing all islands in our study area that have pre­vi­ously had or are suit­able for nest­ing Arc­tic Terns. These islands are in loca­tions which are passed by while con­duct­ing sur­veys for fal­cons, and we can con­duct the sur­veys in a rel­a­tively short amount of time. These are the only sys­tem­atic sur­veys for Arc­tic Terns con­ducted on an annual basis any­where in Greenland.  


Tern nest Bridger getting hit by tern
Arc­tic Tern nest with two eggs. Arc­tic Terns are extremely defensive.


Par­a­sitic Jaeger Geolo­ca­tor Study

His­tory, objec­tives, and pre­vi­ous results of study:  Par­a­sitic Jaegers are a long-distance migrant that breed through­out the cir­cum­po­lar Arc­tic.  Although observed in the south­ern hemi­sphere dur­ing win­ter months, lit­tle to no infor­ma­tion is known regard­ing which migra­tory path­ways or win­ter­ing areas dif­fer­ent geo­graph­i­cal breed­ing pop­u­la­tions use.  In north­west Green­land, Par­a­sitic Jaegers are gen­er­ally uncom­mon, and dur­ing a given field sea­son we are likely to only observe a hand­ful of indi­vid­u­als at most.  That said, over the past 10 years we have located three breed­ing pairs, with the pairs return­ing to the same gen­eral areas to nest in suc­ces­sive years.  This pro­vides us with a unique oppor­tu­nity to cap­ture and tag the adults with geolo­ca­tors.  This infor­ma­tion will not only pro­vide the first spe­cific migra­tory infor­ma­tion on Par­a­sitic Jaegers breed­ing in Green­land, but the species as a whole.

Results from 2019:  Loca­tions where Par­a­sitic Jaegers were cap­tured and tagged with geolo­ca­tors in 2017 and 2018 were vis­ited and nest­ing jaegers were found at one loca­tion. The indi­vid­ual cap­tured and tagged with two geolo­ca­tors in 2018 (one on each leg) was re-captured and still had both geolo­ca­tors attached and func­tion­ing. In 2018 we chose to attach two geolo­ca­tors to this indi­vid­ual after the sin­gle geolo­ca­tor attached in 2017 fell off. We again attached two geolo­ca­tors to this indi­vid­ual and it was released. Two new pairs were found in 2019 but it appeared that both had likely failed and thus we were unable to cap­ture either adult.  

Objec­tives for 2020:  Recap­ture the sin­gle indi­vid­ual tagged in 2019 and search for the other indi­vid­ual tagged in 2017. Visit new nest­ing loca­tions found in 2019 and attempt to cap­ture and tag addi­tional individuals.


Parasitic Jaegar chick Paraitic Jaegar in flight
Par­a­sitic Jaeger nestling. Par­a­sitic Jaeger in flight.


Snow Bunting and Lap­land Longspur Monitoring

His­tory, objec­tives, and pre­vi­ous results of study:  In recent years passer­ine pop­u­la­tions through­out the Arc­tic have been shown to be sig­nif­i­cantly influ­enced by rapidly chang­ing cli­matic con­di­tions.  For exam­ple, the recent increase in storm events dur­ing sum­mer months has been shown to have a detri­men­tal effect on fledg­lings, greatly increas­ing mor­tal­ity.  In Thule we have noted a sim­i­lar trend, with sev­eral large rain events in recent years lead­ing to numer­ous dead fledglings…to the point you sim­ply observe them lying dead when hik­ing the tun­dra.  Addi­tion­ally, changes in both the amount and type of pre­cip­i­ta­tion dur­ing sum­mer months (rain ver­sus snow his­tor­i­cally) may also be affect­ing insect abun­dance and veg­e­ta­tion growth, both of which passer­ines rely upon for food.  As a result of these observed changes in 2010 we began trap­ping both Snow Buntings and Lap­land Longspurs when weather con­di­tions pre­vented us from boat­ing.  Since then we have devel­oped a reg­u­lar trap-line and pro­to­col which we fol­low each sum­mer.  As of the end of 2017 we have cap­tured over 700 dif­fer­ent indi­vid­u­als, with a num­ber of them recap­tured in later years.  As pre­dicted, we have seen extremely large swings in the num­bers of juve­niles caught, with some years hav­ing 4–5 times more juve­niles than oth­ers.  Using this capture/recapture method­ol­ogy we should be able to look at annual sur­vival of both juve­niles and adults, juve­nile recruit­ment into the breed­ing pop­u­la­tion, and changes in the size of the pop­u­la­tion over time. 

Results from 2019:  We cap­tured 41 (29 adults/12 juve­niles) Lap­land Longspurs and 45 (32 adults/13 juve­niles) Snow Buntings, includ­ing a com­bined 22 re-traps. Despite over­all good weather con­di­tions through­out the sum­mer the num­ber of juve­niles was still lower than antic­i­pated, although much greater than 2018.


Num­ber of Lap­land Longspur adults and juve­niles cap­tured each sum­mer from 2010 to 2019.

Num­ber of Snow Bunting adults and juve­niles cap­tured each sum­mer from 2010 to 2019.

Objec­tives for 2020:  Dur­ing peri­ods when we can­not boat we will con­tinue to trap Snow Buntings and Lap­land Longspurs. All indi­vid­u­als (includ­ing re-traps) will be banded, weighed, and mea­sured. Addi­tion­ally, we will begin col­lect­ing mete­o­ro­log­i­cal data from the Thule Air Base weather sta­tion to begin look­ing at what pat­terns we can see between weather events and num­ber of fledg­lings cap­tured each summer.  


Adult male snowbunting 001 Longspurs in trap
Adult male Snow Bunting with orange color band. An adult male Lap­land Longspur and juve­nile longspur in trap.


Nearc­tic Pere­grine Fal­con Geolo­ca­tor and Migra­tion Study

His­tory, objec­tives, and pre­vi­ous results of study:  Over the past 20 years much infor­ma­tion has been col­lected on migra­tory move­ments of Pere­grine Fal­cons through­out their West­ern Hemi­sphere Arc­tic range; how­ever, these stud­ies occurred inde­pen­dently of one another and a large amount of vari­a­tion can occur from year to year based on weather and prey.  Start­ing in 2012, researchers in South­ern Green­land, north­west Green­land, and Rankin Inlet (Nunavut, Canada) began a long-term and large-scale col­lab­o­ra­tive study tag­ging adult female Pere­grines with geolo­ca­tors.  By col­lect­ing data from through­out this large geo­graphic area researchers will be bet­ter able to make com­par­isons of migra­tory move­ments (tim­ing and rate of migra­tion) along with win­ter­ing areas between these pop­u­la­tions.  Fur­ther­more, by col­lect­ing data over a long time span, we will be able to deter­mine what changes if any are occur­ring in the tim­ing of migra­tion, along with poten­tially look­ing at how weather pat­terns may affect both the tim­ing and rate of migra­tion.  The pop­u­la­tion in north­west Green­land is of par­tic­u­lar inter­est since they appear to migrate far­ther than any other known Pere­grine pop­u­la­tion in the world, and are thus more likely to be influ­enced by annual vari­a­tion in weather patterns.    

Addi­tion­ally, data col­lected from geolo­ca­tors will be com­pared with data col­lected using satel­lite trans­mit­ters (his­toric data from 2001–2004) to deter­mine what effect, if any, satel­lite trans­mit­ters may have on Pere­grine migra­tion.  For exam­ple, do Pere­grines car­ry­ing satel­lite trans­mit­ters (12–20 g back­pack units) travel at a slower rate when com­pared to Pere­grines car­ry­ing geolo­ca­tors (1–2 g, attached to color band)? 

To date we have recov­ered geolo­ca­tors from five adult female Pere­grines.  Based on results from our study area, south­ern Green­land, and Canada it now appears that migra­tion dura­tion of Pere­grines wear­ing PTTs is sig­nif­i­cantly longer than those tagged with geolo­ca­tors.  While depar­ture dates are very sim­i­lar between indi­vid­u­als tagged with either type of unit, arrival dates at win­ter­ing areas are approx­i­mately 25 days later.  This is one of the first stud­ies of this type show­ing the poten­tial detri­men­tal effects, and bias, of using PTTs in migra­tion studies. 

Results from 2018:  Unfor­tu­nately, no geolo­ca­tors were recov­ered in 2018. Of the four tagged females from 2017 one was recap­tured and both the color band (Dar­vic) and geolo­ca­tor had fallen off, two of the females were at cliffs that were not occu­pied in 2018, and the fourth appeared to have lost her geolo­ca­tor. This is the first year we have encoun­tered large scale prob­lems with geolo­ca­tors falling off and plas­tic color bands (Dar­vic) fail­ing (also see Par­a­sitic Jaeger sec­tion). As a result, we began mod­i­fy­ing alu­minum color bands and will only use those in the future. Two new females were tagged with geolo­ca­tors in 2018, one attached to a plas­tic Dar­vic color band (we did not yet have alu­minum bands ready) and one to a mod­i­fied alu­minum color band.

Objec­tives for 2019:  We will attempt to recover the two geolo­ca­tors deployed in 2018 in addi­tion to deploy­ing geolo­ca­tors on up to four addi­tional female Peregrines. 





Adult female Pere­grine Fal­con with geolocator. A geolo­ca­tor on an adult female Pere­grine Falcon.


Methyl Mer­cury and Sta­ble Iso­tope Study

His­tory, objec­tives, and pre­vi­ous results of study:  While not pro­duced in the Arc­tic, many pol­lu­tants (e.g., per­sis­tent organic com­pounds and heavy met­als) that orig­i­nate in mid-latitude indus­tri­al­ized nations are trans­ferred to the Arc­tic via water and atmos­pheric con­di­tions. In par­tic­u­lar, methyl mer­cury has recently become a major con­cern, with a wide range of extremely neg­a­tive effects asso­ci­ated with ele­vated lev­els in many bird species (e.g., abnor­mal incu­ba­tion and feed­ing behav­ior, reduc­tion in hatch­ing suc­cess, etc.). Fre­quently, species higher up the food web (higher trophic level) have sig­nif­i­cantly greater con­cen­tra­tions, in par­tic­u­lar marine-feeding bird species such as Thick-billed Mur­res and Black Guille­mots which feed on small fish which in turn feed on smaller zooplankton.  

Results from a study we con­ducted from 2010-12 showed (24 species, 625 sam­ples) that 11 of the species sam­pled were at low risk for mer­cury tox­i­c­ity. Of more con­cern, some Thick-billed Murre, Black-legged Kit­ti­wake, and Pere­grine Fal­con indi­vid­u­als had had high enough blood mer­cury lev­els to put them at medium risk for mer­cury tox­i­c­ity. Adult female Pere­grine Fal­cons had the high­est recorded blood mer­cury con­cen­tra­tions of any of the sam­pled species in our study area, which was unex­pected as they gen­er­ally prey on both seabirds (high mer­cury con­cen­tra­tions) and passer­ines (low mer­cury con­cen­tra­tions). Gen­er­ally speak­ing, for most of the species sam­pled in our study they had the high­est blood mer­cury con­cen­tra­tions pub­lished to date.

Results from 2019:  Dur­ing the 2019 field sea­son we col­lected blood and feather sam­ples from 11 dif­fer­ent species total­ing 81 sam­ples. For the major­ity of species col­lect­ing occurred at the same exact loca­tions as dur­ing our pre­vi­ous mer­cury study, which will allow us to make direct com­par­isons with his­tor­i­cal data. 

Objec­tives for 2020: Lim­ited fund­ing has been received to again begin inten­sive col­lec­tion of blood mer­cury sam­ples to repeat much of our study from 2010–2012. While all avian species will be tar­geted, par­tic­u­lar atten­tion will be given to species for which we had small sam­ples sizes (e.g. shore­birds) in the pre­vi­ous study, species which had sur­pris­ing results (e.g. very high Hg lev­els for their trophic posi­tion), and species/age classes for which no sam­ples were col­lected (e.g. adult Gyr­fal­cons), and species for which sim­i­lar stud­ies are occur­ring else­where (e.g. Thick-billed Mur­res, Black-legged Kit­ti­wakes, etc.).


Kanger­lus­suaq Area, central-west Greenland

Pere­grine Fal­con Monitoring

His­tory, objec­tives, and pre­vi­ous results of study:  We have mon­i­tored the Pere­grine Fal­con pop­u­la­tion in the Kanger­lus­suaq area from 1972–2006, 2008, and 2012–2013, result­ing in a large num­ber of pub­li­ca­tions.  While con­tin­ued large scale annual mon­i­tor­ing has not been pos­si­ble, we attempt to sur­vey the area every 3–5 years to col­lect data on repro­duc­tion, nest­ing chronol­ogy, and nest site char­ac­ter­is­tics.  Addi­tion­ally, sim­i­lar to Thule, when pos­si­ble chicks are ringed and sam­pled and molted feath­ers, egg shell frag­ments, and prey remains are col­lected, all to be used in other projects (e.g., adult turnover stud­ies, pol­lu­tant analy­sis, sta­ble iso­topes, genetics).

Results from 2019:  Approx­i­mately 20 known Pere­grine Fal­con nests were sur­veyed dur­ing 2020 and results are still be analyzed.

Objec­tives for 2020:  Lim­ited sur­veys will occur for Pere­grine Fal­cons in the Kanger­lus­suaq area dur­ing sum­mer 2020.


Peregrine chicks and egg
Recently hatched pere­grine fal­con chicks. An adult female pere­grine falcon.