If you click on any images in the blog, it will be opened in a separate window, will be larger and it will be easier to see detail.

Blog posts after 1 Feb 2018 about Steppe eagles tracked from Oman can be found at the Steppe eagle blog

Wednesday, December 23, 2015

More about electrocution

Worldwide electrocution is a huge problem for large birds, including many eagles and vultures. Many of the species affected by electrocution (like the Egyptian vulture) are also endangered, and electrocution contributes to their poor conservation status.  Click here to access a paper on electrocution of Egyptian vultures in East Africa by Ivaylo Angelov and others.  If you Google the words "bird electrocution power lines" you will be able to see loads of images of many species that have been electrocuted, mostly large species and many predatory birds

Oman is recognized as a global stronghold for Egyptian vulture because of its seemingly stable breeding population, and as a destination for many migrants from farther north.  It is also an important winter destination for migrating eagles, like the endangered Steppe Eagle (which is on the 100 Baiza note) and Eastern Imperial Eagle.  Oman was thought to be relatively safe for Egyptian vultures, and other species, although the possibility that birds were being electrocuted was always there.  Sadly, this incident shows that electrocutions occur, we just don't know at what rate.
Juvenile Egyptian vulture perched on a dangerous power line in Oman. (Photo: A. Kovac)

While the news of this bird's death is sad, and the prospect that more birds are electrocuted is worrying, there is a positive side.

1) Oman is a developing country and is only now installing much of its power transmission network, a process that will grow as the human population grows and human activities are started up in new areas.  This means that using pylon designs that reduce electrocution during this development phase could help avoid future electrocution at almost no additional cost.  Much has been done in North America http://www.aplic.org/, Europe and Africa to design such safe pylons.

Juvenile golden eagle electrocuted on a power line in North America (Photo: USFWS)
2) The distribution in Oman of the large birds that are most vulnerable to electrocution is somewhat predictable.  Many of the migrating raptors are also scavengers and concentrate near rubbish dumps and many of the resident raptors are territorial and use particular habitats.  This means that "sensitivity maps" can be drawn that identify areas where risk is particularly high, and these areas can then be the focus of efforts to reduce that risk.  In doing this the biggest conservation benefit will be realized sooner and with the least effort and cost.

Wintering Steppe Eagles on a dangerous pylon near a rubbish dump in Oman (Photo: A. Kovac)
3) In some cases the most immediate solution is to change the pylons that are most dangerous.  This, of course, costs money.  Because of this problem bird biologists have long worked with transmission line engineers to design cost-effective solutions or retro-fitting.  Indeed, in the long run these modifications could save money by reducing the number of times engineers have to visit sites of electrocution.  Reducing electrocutions would also have the advantage of reducing power outages to customers.

If you'd like to read more about this problem, click on the links below.


Monday, December 21, 2015

Sad News

It is with great regret that I report that the Egyptian vulture we have been tracking since January 2015 has died.  The Environment Society of Oman (ESO) has posted something on Facebook (https://www.facebook.com/EnvironmentSocietyOfOman/?fref=ts).  The last transmission we had from this bird was in the afternoon of 13 December from a location just north of the Sifa Resort.  Sensors on board the transmitter showed it to be working normally, but the transmissions ended abruptly.  Below is a map of the locations in the week before the end of transmissions.

Vulture locations in the week before its death.
Last two locations
We waited for another transmission cycle to pass before worrying because other things can affect transmissions, like the amount of sunlight or whether the bird is in view of a satellite.  On 19 January Dr. Glyn Barret went in search of the bird, using the coordinates of its last location.  He found it dead from apparent electrocution under power lines and a transformer.  The transmitter was apparently fried.  See below.

Dead satellite tagged Egyptian vulture below power lines near Sifa. (Photo G. Barrett)
Last location.  One can see the shadow of the pylons in the picture above.

Dead vulture.  Transmitter can be clearly seen in the middle of the picture.(Photo G. Barrett)
The dead vulture during happier days (Photo W. AlFazari).
Worldwide electrocution is a huge problem for large birds, including many eagles and vultures.  Many of the species affected by electrocution (like the Egyptian vulture) are also endangered, and electrocution contributes to their poor conservation status.  Click here to access a paper on electrocution of Egyptian vultures in East Africa by Ivaylo Angelov and others.

Oman is recognized as a global stronghold for Egyptian vulture because of its seemingly stable breeding population, and as a destination for many migrants from farther north.  It is also an important winter destination for migrating eagles, like the endangered Steppe Eagle (which is on the 100 Baiza note) and Eastern Imperial Eagle.  Oman was thought to be relatively safe for Egyptian vultures, and other species, although the possibility that birds were being electrocuted was always there.  Sadly, this incident shows that electrocutions occur, we just don't know at what rate.  Indeed, it may have been that the other vulture we tracked, which disappeared in March, was also electrocuted.

In the coming days I'll post more information on the issue of electrocution and birds, so hopefully this sad event will have some positive effect.

Thursday, December 10, 2015

Early December 2015

The tracked Egyptian vulture has settled into the area where it has spent most of its time since it was captured 11 months ago.  Early in the month it was located mostly inland from Sifa, then during 4-5 December it was on the coast south of Quriyat, and roosting on a power pylon SW of the town. In recent days it has moved back up to range in villages along the Muscat to Quriyat road (الطريف Al Traiff
الفياض Al Fiadh, حيفظ Heifdh) and made quick journey to the area around Yiti.  Although back north of the Hajar Mountains, it seems not to have visited the rubbish dump at Al Multaqua in the last two weeks.

Movements of a sub-adult Egyptian vulture during early December 2015.

Monday, November 30, 2015

End of November 2015

During the past week the satellite tracked bird has moved around quite a bit.  During 23-24 November it was mostly located east of Sinaw.  During 25-28 November it moved NE and was located NE of Ibra.  Late on the 28th, it moved across the Hajar Mountains to a place just west of Sifa, not very distant from the Al Multaqa rubbish dump where it was first captured.  By the 30th it had moved south towards Quriyat.

Egyptian vultures are, of course, scavengers, and have the ability to cover huge distance in search of food, and may need to do so when food availability is low.  However, between the large and small rubbish dumps near the towns and cities of Oman, the shoreline and the death of animals in rural areas it seems that there is a lot of food around in Oman for vultures.  We don't know why this bird made these relatively long movements.  Maybe with more data and data from other birds, we'll come to better understand vulture ecology in Oman.

Movements of an Egyptian vulture during 23-30 November 2015.

Thursday, November 19, 2015

Mid-November 2015

Since January when we started tracking this vulture, it has moved mostly in the area between Muscat and Quriyat, and has stayed north of the eastern Hajar Mountains.  In the beginning of November it made a move to the south, crossing the mountains and spending time around Ibra.  In the past few days it has been mostly near Sinaw, and when one looks closely at individual locations, it seems it has been visiting the rubbish dumps at Sinaw and at other smaller villages, and roosting at a hill SE of Sinaw.

Movements of a 3rd yr Egyptian vulture during 12-18 November 2015.
Zoomed image showing movements near Sinaw.
Further zoomed image showing a view from the north of a hill and cliffs where the vulture has been roosting.

Wednesday, November 11, 2015

Early November

In the last week the Egyptian vulture we have been tracking has moved out of its normal range, north of the Hajar Mountains and south of Muscat.  On 4-5 November it was around Quriyat.  Quriyat has been visited before by this vulture, which seemed then to forage at the main rubbish dump and along the coast.  On 6-8 November this bird headed south over the mountains and visited areas near the town of Ibra.  Ibra is where the other bird we fitted with a transmitter disappeared about 6 months ago.  On 10 November it moved farther south and east and seems to have also made a quick sojourn into the Wahiba Sands.  By 11 November it had moved back north to the foot of the mountains about 6 km east of the town of Adh Dhahir.  This is the first time this bird has moved south of the mountains.  We'll have to wait to see what happens next.

Movements of third year Egyptian vulture during early November 2015.
Also during the past two weeks we have been working on a short film about Egyptian vultures.  Most of the work was at the New Al Amerat rubbish dump.  The aim of the film is to raise awareness in Oman about vultures, raise awareness in other countries about the importance of Oman as a stronghold for Egyptian vultures, and perhaps a way of approaching funders for future work.  That film should come out soon after the New Year.

Thursday, October 15, 2015

Early October 2015

For those of you who are in Oman, the flow of Egyptian vultures from areas farther north has begun. These birds will include adult birds that breed in northern parts of the range (probably mostly from western and central Asia) and their offspring.  Because of this the numbers of Egyptian vultures using the rubbish dumps in Oman are climbing, and will be high throughout the winter.  The incomers will, of course, mix with the resident Omani Egyptian vultures and Lappet-faced vultures, and migrant eagles at the rubbish dump.  Winter is a good time in Oman for raptors.

The bird we have been tracking has spent much of its time over the last 2 weeks at the main Muscat municipal rubbish dump.  This is despite the work that is going on there as the dump is undergoing a planned expansion.  You can see the expansion if you look at the site on Google Earth, or, of course, you can just go by and see for yourself.
Movements of a radiotagged Egyptian vulture during the first two weeks of October 2015.

Tuesday, September 29, 2015

Late September 2015

The Egyptian vulture we have been tracking has spent the last three weeks moving around between the Al Multaqa rubbish dump, the coast and villages nearby.  This is where it has spent most of its time over the last 8 months.

Movements of vulture during 21-28 2015.
 Interestingly, we can see below that there is work going on at the dump itself.  Presumably this is part of the $37 Million/14.25 Million OMR expansion Sita-Suez won earlier in the year.  Click here to read more about that upgrade/expansion.  In fact, Oman is upgrading its waste disposal across the country.  Such upgrades are crucial for human health, and need not negatively affect scavenging birds, like the globally endangered Egyptian vultures that use the rubbish dumps.  Indeed, by their very nature, vultures provide an important "ecosystem service" by feeding on rubbish, and thereby removing it from the environment.  They provide this service 365 days a year, for free.

View of the rubbish dump.  Compare with the image posted on this blog on 4 September 2015.

Thursday, September 10, 2015

Eight month review

Its been about 8 months since we captured two Egyptian vultures at Al Multaqa, and fitted them with GPS satellite transmitters.  The maps below are of all the GPS locations.  Together they show the areas most used by the tracked vultures.  While this blog usually puts up maps that span shorter periods of time, these longer-term maps show more accurately the areas used by the vultures and will be important to understanding how they use their environment and what needs to be done to conserve Egyptian vultures in the long-term.

GPS locations of Egyptian vulture (143581).  This bird stopped transmitting in early February 2015.

GPS locations of Egyptian vulture (143580).  This bird is still transmitting and moving around northern Oman.

Friday, September 4, 2015

27 August-3 Sept 2015 and Vulture Awareness Day

Don't forget that tomorrow is Vulture Awareness Day  http://www.vultureday.org/2015/index.php.

So that you are aware of what the radio tracked vulture in Oman is doing... During this week our vulture seemed to favour feeding at main Muscat municipal rubbish dump at Al Multaqa.  It has been remarkable (to me at least) how little time this bird has spent at the rubbish dump since it was fitted with a transmitter back in January.  The map below shows its movements over the last week.
Movements of subadult Egyptian vultures during 27 August - 3 September 2015.
The map below shows that the bird has indeed been at the rubbish dump, and the preference for roosting at a particular electricity pylon about 500 m south of the dump.

Locations at the Al Multaqa Rubbish Dump during end of August 2015.
Map showing the importance of this electricity pylon to the tracked vulture during the last days of August 2015.

Monday, August 31, 2015

National Geographic's Great Nature Project helps vultures

A hooded vulture from the Gambia.
Image from National Geographic's Great Nature Project page.
In conjunction with the upcoming Vulture Awareness Day (5 Sept), National Geographic’s Great Nature Project will feature a collection of their photographic records on vultures. The Great Nature Project is a citizen science project that is documenting the Earth’s biodiversity through the sharing of photographs alongside some standard information about each photo. You can find out more about it here.http://greatnatureproject.org/faq The featured collection on vultures can be viewed here http://greatnatureproject.org/collections/37.
This support from National Geographic will help raise the global profile of vultures, and get the public excited about them. You can help support this initiative by registering, and submitting your vulture photos here. http://greatnatureproject.org/participate

Friday, August 21, 2015

Two satellite systems, more complete coverage

After spending some time last week around Bid Bid, the vulture we have been tracking has moved back east, and has been visiting the rubbish dump at Al Multaqua and the coast around Yiti.  These areas are where it has spent most of its time since being captured seven month ago.  Below are maps of the movement of the vulture over the last week.

In previous posts we explained that the technology we use to track the birds actually estimates locations in two ways, using two different satellite networks.  One is the GPS satellite network (green locations), in which the package attached to the bird listens for signals from geo-stationary satellites, then uses those signals to calculate the package's location on the earth.  That location is then uploaded via the Argos system of satellites and sent to us.  GPS locations are highly accurate, but can be expensive in terms of energy to acquire.  The second satellite network used to locate the package on the bird is the Argos system of satellites (red locations).  Argos system satellites are orbiting the earth, listening for signals from transmitters like the one on our vulture.  The transmitter is sending the GPS location via the Argos system, but also sends a stable signal, from which the orbiting Argos satellites can calculate the location of the package using the Doppler effect (the shift in frequency as a transmitter and receiver move relative to one another.).  Argos locations are generally less accurate than GPS, but require less energy.  The differences in the two maps arise not only from the different accuracies of the two systems, but also the different duty schedules of the two systems resulting from the need to manage power to acquire GPS locations.  So, while the Argos locations are generally less accurate than the GPS locations, they can be estimated more often and thereby fill in gaps in data collection time.
Locations of tracked vulture during 12-20 August 2015 as estimated by the GPS system of satellites. 

Locations of tracked vulture during 12-20 August 2015 as estimated by the Argos system of satellites. 
Generally speaking, vultures suffer from a poor public image.  Click on this link to view a page that discusses the truth about vultures and how they are important to human well-being.  http://www.bbc.com/earth/story/20150713-the-truth-about-vultures

Sunday, August 9, 2015

Move towards Bidbid

143580 has moved operations to the west.  In the last week it has been making daily visits to the rubbish dump at Bidbid, and roosting in the mountains just west of the Al Sareen Nature Reserve.
Map showing use of Bidbid rubbish dump (orange circle) during first week of August 2015.

Movements of third year Egyptian vulture during first week of August 2015.  Shaded area on right is the Wadi Sareen Nature Reserve.

Monday, August 3, 2015

Late July 2015

The vulture we are tracking has been making some short journeys around northern Oman. The map below is of its movements during 19-31 July.  On 19-20 it was located in the mountains to the east of Samail, it then flew over and spent some days in the hills near the coast near Yiti.  On 31 July it had moved back and was likely feeding at the municipal rubbish dump at Al Amerat.  When one zooms the maps one can see that many of the locations are at electricity pylons.

We have been tracking this bird for almost 7 months now.  During that time, it has moved solely within northern Oman from Quriyat in the southeast to Barka in the northwest. Much of its time has been spent roosting on electricity pylons and communications towers.  It has foraged in villages, on the coast, and at large rubbish dumps, suggesting that the large rubbish dumps are not the only source of food.  It has spent a small amount of time in the protected area of Wadi Sareen, but has not shown any signs of establishing and holding a breeding territory. This is not surprising because this bird is not yet adult.  Also, this bird showed no signs of migrating.  We do not yet know if this bird was raised in Oman and will attempt to breed there or whether it is from somewhere else (farther north) and will migrate back to attempt to breed once it has become an adult.

Movements of subadult Egyptian vulture during 19-31 July 2015

Friday, July 17, 2015

Egyptian vulture workshop in Bulgaria

Earlier this month over 70 Egyptian vulture experts and conservationists gathered in Sofia, Bulgaria to discuss and seek remedies for the continuing decline of the this species.  The gathering was convened under the auspices of the "Return of the Neophron" Project being carried out by the Bulgarian Society for the Protection of Birds, which is a Life +  Project funded by the European Union. Click here to read more about the meeting.  Four attendees with special interest in vultures in Oman, Maia Sarouff-Willson, Mansoor Al Jahdahmi, and Mike McGrady, participated.

Egyptian vulture is a globally endangered species, which is suffering large declines in most parts of its range. The declines seem to be the result of a complicated web of a large number of threats acting across its range.  Because the Egyptian vulture is migratory in part of its range, the threats are international, regional, and seasonal in character... Like I said...its complicated.  Click here to visit BirdLife's fact sheet for Egyptian vulture.

Photo: Dimitar Gradinarov
Attendees at the Workshop on Egyptian Vultures held in Sofia, Bulgaria, July 2015.
By the end of the summer, the outcomes of the conference, including a draft Egyptian Vulture Flyway Action Plan, will have been assembled, reviewed, and made available at the Return of the Neophron web site.

One outcome of the meeting that can be reported is that all participants were very interested in Oman because it seems to be a stronghold for this species, both in terms of its resident breeding population and its importance as a winter-time destination.  While we are in the very early days of understanding the Egyptian vulture in Oman, it seems that the sultanate may hold the largest breeding population in the Middle East, and be the most important safe place for birds from farther north (probably mostly Asia) to winter.  More work like that being displayed on this blog and being done by the Environment Society of Oman is necessary.  Filling the gap in our understanding of Egyptian vulture ecology in Oman will be one of the recommendations coming from the workshop.  You can download a declaration by the workshop attendees by clicking here

So, that you don't suffer from withdrawal, below is a map of the movements during 10-17 July of the Egyptian vulture we are tracking via satellite. In this week it has been moving between the coast and villages slightly inland and SW of Yiti.

Movements of an Egyptian vulture fitted with a satellite-received transmitter during 10-17 July 2015.

Monday, June 29, 2015

Late June 2015

143580 continues to move around just south of Muscat, and has shown some recent preference for roosting in cliffs in the Al Sareen Nature Reserve, about 7 km south of the Al Amerat rubbish dump.  It has also spent some time during the last week in the area just west of Yiti.

Movements of subadult Egyptian vulture in late June 2015

Sunday, June 21, 2015

Mid June 2015

The vulture we have been tracking has probably just had a birthday.   This also means that his plumage is probably changing and he will look a bit different (more white) than he did when we caught him.  I keep calling 143580, "him", but it might be a "she".  We'd need to analyse the blood to determine its sex.

In the last weeks 143580 seems to have abandoned Quriyat, at least temporarily.  It has mostly been south of Muscat, and has made the occasional visit to the Al Amerat rubbish dump.  on 20 June, It visited Al Sareen Nature Reserve.

Movements of a three year old Egyptian vultures during 14-21 June 2015.

Wednesday, June 10, 2015

Cyclone Ashobaa

Looks like Oman might get hit by cyclone Ashobaa http://www.accuweather.com/en/weather-news/oman-to-pakistan-remain-on-ale/48386959 It is unlikelythat such an event would have much effect on our tagged Egyptian vulture or on the breeding vultures in Oman, although they maynot be able to forage as efficiently if there is a lot of rain.  That effect will likely pass relatively quickly.

Early June 2015

The young bird we have been tracking has moved up from Quriyat toward Muscat, and on 1 June visited the municipal rubbish dump at Al Amerat, and the northern part of Wadi Sareen Reserve.  Since then it has been moving in the mountains to the east of Al Amerat.  Just to remind you, this is a bird that is too young to breed, but it seems to be a bird that was probably reared in Oman.  It may take another three years before we know if and where it will breed.
Movements of a second year Egyptian vulture during 1-9 June 2015.

Wednesday, May 27, 2015

Egyptian vulture in Wadi Sareen

The vulture we have been tracking, which is now about 2 years of age was near Quriyat during the beginning of this week, moved up to a location between Al Hajar and Yiti on the 20th and 21st, then moved back down to Quriyat.  After that it moved west and was last located (26 May) in the mountains of the Wadi Sareen Reserve, east of Tool.  Although no comprehensive survey of Wadi Sareen for Egyptian vultures has been made,  The reserve and the rest of the eastern Hajar Mountains likely hold a healthy breeding population of this globally endangered species.  It seems also that the mountains are used in the winter by vultures that have migrated to Oman from northern areas.  Of course, the Wadi Sareen Reserve is well known for its population of a globally endangered mammal species, the Arabian Tahr.

Movements of a two year old Egyptian vulture, most recently located in the Wadi Sareen  Reserve, which is managed by the Office for Conservation of the Environment.

Saturday, May 16, 2015

Mid May 2015

The vulture we have been tracking has fallen into a steady routine.  It seems to divide its time mostly between the rubbish dump at Quriyat, the coast, a roost site inland and the area around the village of Hayl al Ghaf.  While this seems pretty unexciting, most of what we know about the movements of Egyptian vultures is from migratory populations and breeders.  This is a non-breeding bird.  Although non-breeders are often viewed as of secondary importance, obviously without surviving immature birds there would be no future generations of breeding adults.  For this reason, these data are useful for conservation.

Movements of immature vulture during early May 2015.

Zoomed view of map above showing the use of the coast, the local rubbish dump, the area around Hayl al Ghaf and a roost site at a communications tower.

Thursday, May 7, 2015

First week of May 2015

For the last few weeks, the immature Egyptian vulture that we have been tracking has been spending its time in the Quriyat area, mostly just south and southwest of the town.  It seems also to spend alot of time roosting on a communications tower and foraging down on the beach. (Reeminder: If you click on the maps below, they should open up in another window and be larger and easier to see.)

Movements of an immature Egyptian vulture during the first week of May 2015
Location of a roosting site for the Egyptian vulture we are tracking on a communications mast near Quriyat. 

Saturday, April 18, 2015

Mid-April 2015

In recent days the vulture we have been tracking has moved south and has been spending its time near Quriyat, or more accurately near the Quriyat rubbish dump. The Quriyat rubbish dump, like the one at Muscat, is a good place to see vultures.  In the last 8 months or so, the dump has been being upgraded and modernized, but vultures like ours still visit it.  We already know that the Muscat dump, which is probably the most modern in the country is visited on a daily basis by many scavenging birds, including Endangered Egyptian vultures and Vulnerable Lappet-faced vultures, both of which are resident in Oman.

Movements in mid-April 2015 of an Egyptian vulture fitted with a satellite-received transmitter

Tuesday, April 7, 2015

First week of April 2015

During early April, the Egyptian vulture we are tracking continues to be moving mostly between villages along the Muscat -Quriyat road.  If one zooms in on the locations, you can see the shadows of the electricity pylons, illustrating just how much time this bird spends perched on them. This bird has also made journeys out to the coast between Sifa and Yiti, and at least one journey to the beach south of Quriyat (Click on the map below to enlarge).

Below is a link to a kml file that you can download and then open up in Google Earth.  Once you do that you can zoom into the places this bird has visited and see the pylons I mention above.  To download the file, click on the link (this will open up in Google Maps, but will show nothing, so don't pay any attention to it), then go to File, then Download.  Save to your computer, then open using Goggle Earth.  Let me know if this does not work, and I'll try to figure out something else.

EV kml April 2015

Movements of satellite tracked vulture during 31 March-7 April 2015

Monday, March 23, 2015


Although nothing much seems to be happening with the marked vulture, that in itself is interesting because it implies that there is enough food around for this bird to move within a relative small area.  The linear nature of the locations are in part a result of this bird (like other Egyptian vultures) spending much of their time perched on power line pylons.  Another interesting thing is that this bird has not spent much time at the site where it was caught:  the Muscat municipal rubbish dump marked on the map as Al Amerat.  Many tons of rubbish are disposed of at that dump daily, and large numbers of Egyptian vultures can be seen there, especially in the winter, when migrants from Eurasia are present. (If you click on the map is should open in another window and be larger and easier to see.)
Movements of radiotagged Egyptian vulture during 16-23 March

Wednesday, February 25, 2015

19-25 February 2015

In the last week 143580 has been moving around areas familiar to it. What is interesting is that during that whole week, it seems that the vulture never once visited the municipal rubbish dump at Al Amrat (where it was caught).  Currently it is moving between Al Hajar and Al Fayad, villages near the main Muscat-Quriyat road.  If you look back at earlier blog posts, you will see that this bird has used these areas before.  The assumption (at least my assumption) was that the Al Amerat rubbish dump played a huge role to the birds there, and that the birds visited daily.  This is apparently not the case, and implies that many more Egyptian vultures are using the area than we see at Al Amerat, and during the winter sometimes over 400 Egyptian vultures can be seen at the rubbish dump there!

Movements of 143580 during the week starting on 19 Feb 2015. (Click on the image and it will open in a new window, and be easily enlarged.)

Friday, February 20, 2015

Tutorial on the Technology

This blog post will be a short tutorial on the technology used to track the vultures.

The transmitters we use are "GPS PTTs" (Global Positioning System Platform Transmitter Terminals), and essentially they use two sets of satellites to locate the bird and to transmit data on its position and other information about the transmitter (battery status, activity of the bird, etc.) back to earth (us).  These two satellite processes are somewhat independent, but also integrated.  When working properly what happens is this:

The GPS receiver in the PTT calculates on a regular basis its location using the GPS system of satellites and stores that data on board the PTT.  Every two days the transmitter then turns on for a period of 10 hours and uploads that data via the Argos system of satellites, which then transmits the data to a ground station, which then forwards the data to us. The transmission of data via the Argos system also contains the other information about the tag or from sensors in the tag (when you hear the transmission it sounds like a fax).  The transmission signal sent by the PTT has not only those data, but has a stable signal pulse that is used by the Argos system to calculate an estimate of the PTT's position using geometry, the Doppler effect and information on the location, trajectory and speed of the satellites.

While this all sounds a bit complicated, the main tangible result is that for every bird we are tracking we get two sets of location data; GPS data and Argos data.  While the GPS data is typically more accurate, it takes more energy to incorporate the GPS technology, so for smaller birds Argos-only locations are possible.  This is not a problem for Egyptian vultures, and so we get both.

Below are examples of the Argos data and GPS data for the same bird over the same period of time, so that you can see the difference.  However, you can also see the similarities, which highlight that this bird has been making regular visits to the rubbish dump at Al Amerat and has recently be near Al Hajar.

GPS locations of 143580 during 30 January - 19 February 2015.
Argos locations of 143580 during 30 January -19 February 2015

Thursday, February 19, 2015

Sorry for the silence

I only realized today that we had not posted anything for a while.  Sorry.

Well, its a bit of good news and (apparent) bad news.  Here's the bad news.

143581 has gone missing.  It last transmitted on 4 February from a location just north of Ibra.  We waited some time hoping that we would get some transmission, but nothing yet.  The Environment Society of Oman sent one of their field biologists to investigate, but found nothing (which isn't entirely surprising),  So, we hope to mount a bigger effort in the near future to try to find out what happened.  Below is a map of the bird's movements between 30 January and 4 February.

Movement of 143581 during 30 January - 4 February 2015
The good news is that 143580 appears to be doing fine.  Since the end of January it has moved north and has been moving regularly between the Muscat municipal rubbish dump at Al Multaqa and the Al Amerat area of Muscat.  In Al Amerat it has been perching frequently on the high voltage powerline pylons.  In recent days it has been spending some time near Al Hajar in Wadi Aday.

Movement of 143580 during 30 January - 19 February 2015.

Monday, February 9, 2015

Early February 2015

The Egyptian vultures we are following via satellite continue to provide interesting information.  It's not that they are doing anything unusual, its just that we have so little information on this species in Oman, and so everything is new.  Below is what the birds have been doing for the last week or so.

143580 (red) wandered around early in the week, and has most recently returned to the rubbish dump where it was captured.  The behaviour of the birds since trapping has suggested that it was a negative experience for them, but with this bird returning to the site, it seems also that they recover from the disturbance in terms of avoiding the site.

143581 (blue) had been foraging south of Barka, but has since moved farther south, crossing the eastern Hajar Mountains, and is currently located near Ibra.

Movements of two Egyptian vultures during the first week of February 2015.