Graphs

I went through each day of observation for each pair and added all of the observations together to create some graphs to show the breakdown of the behaviors for the individual birds in each pair.

Parasitic Jaeger Pair 1 was observed for a total of 166 minutes and this is the graph below.

I also made a scatter plot for the distances I recorded for when each pair began defending against me as I approached their nests.  You can see that the distance increases as incubation length (the date) increases. If I had a better idea of when they actually initiated their nests, and was able to record more points, the X-axis would look differently, but for these purposes it is just the date the distances were recorded. The date is valued as the day of the year; for example June 16th is day 167 of the year. I appreciate questions and suggestions for changing any of these graphs, so please share if you have them.

Parasitic Jaeger Pair 2 was observed for a total of 241 minutes and this is the graph below.

I already stated before, that based on these observations and information from other studies by Martin and Barry from 1978, the female primarily attends the brood, so the female is likely the Light Morph of PAJA Pair 2. Below is the chart for the distance an observer could be from the nest before the pair began defending.

There is another study by Maher from 1974 that states, "repeated visits by humans to a nest result in reduced aggression." However, based off my observations I would say that they increase aggression, at least by increasing the distance a potential predator can approach before they defend against that predator.

Well, that is it for these observations and this blog. Thanks for reading and please leave comments, questions, and whatever you want to share with me!

July 4th 2013, PAJA Pair 2

This might be the final time I am able to observe either pair. Both chicks of PAJA Pair 2 have hatched and as far as I can tell the single egg of PAJA Pair 1 has also hatched. I observed Pair 1 today, and they were defensive but not much when I was close to the nest. When I checked the nest there was no egg so they likely have a chick in the area but I did not see it. Since the chicks will now be able to move around, it will not be easy to observe them, even though they will stay close to the nest for 2-3 weeks. In my observations of PAJA Pair 2 yesterday, I have added a new behavior. Although I have Brood defined as attending brood/young, I did not include in the definition the act of feeding the young. So I added Feeding which is defined as bringing food to young and feeding them. I was too far away to tell what was being given to the chicks, or which was receiving the food.

PAJA Pair 2              Date: 7/4/14        Time spent observing: 13:14 – 14:34

Temperature: 56 F     Wind 11 mph      30% Cloud Cover

Type of Behavior	Total Time Dark Morph	Percent time spent doing behavior	Total Time Light Morph	Percent time spent doing behavior
Defending	8	10	6	7.5
Incubating	0	0	0	0
Hunting/Foraging	34	42.5	0	0
Preening	4	5	1	1.25
Loafing	27	33.75	8	10
In flight	3	3.75	0	0
Altercation	2*	2.5	1*	1.25
Brood	1	1.25	64	80
Feeding	1	1.25	0	0

Total time spent observing: 80 minutes

* = Altercation with King Eider pair. They were dive-bombing them and the eiders were fighting back.

With these observations, I can conclude that the female of the pair is in fact the light-morph. I was hoping to get that down for Pair 1 as well, but am unlikely to figure it out. 

Pretty freshly hatched chick in nest

More alert chick just outside of nest

Both chicks

Below is an updated version of the proximity to nest table I included in the last post for PAJA Pair 2. According to these observations, they do indeed increase their defensive behavior as the eggs are closer to hatching and when they have young. I also saw this with Pair 1, and am thinking the day the fox was in the area, the chick may have been hatching or hatched. 

Date	Distance Observer from nest when pair began defense (in meters)
6/16/14	40
6/19/14	66
6/19/14	30*
6/23/14	78
6/27/14	95**
6/27/14	106**
7/4/14	129

* = distance I was able to stand from the nest when the bird went back to incubating, this could be due to cold weather

** = only observed the proximity to the nest when they began to defend, as I was busy doing the other surveys in the area for that day

Light-morph in flight

A Few Notes and Photos

Things have been very busy since my last observation. So aside from going by the nests and getting some points for proximity to the nest when the pairs begin to defend, I don't really have anything to report. I would have liked to get out there more, but of course, work comes first here when the season goes by so quickly. Below are just some tables I threw together with the distances I recorded for when each pair began their defensive behaviors as I approached their nests.

PAJA Pair 1

Date	Distance Observer from nest when pair began defense (in meters)
6/16/14	100
6/21/14	90
6/21/14	83*
6/29/14	105**
6/29/14	200**
6/29/14	110**
7/3/14	210
7/3/14	147

* = I was observing them from 83m when the Dark morph saw me and chased me off, to where I then observed them from 109m

** = day the Arctic Fox was in the area, the three points are varying times the PAJA pair defended against us when we were working on the other surveys in the area

PAJA Pair 2

Date	Distance Observer from nest when pair began defense (in meters)
6/16/14	40
6/19/14	66
6/19/14	30*
6/23/14	78
6/27/14	95**
6/27/14	106**

* = distance I was able to stand from the nest when the bird went back to incubating

** = only observed the proximity to the nest when they began to defend, as I was busy doing the other surveys in the area for that day

There are already baby birds (goslings and shorebirds) around. I have even seen some gull chicks, so likely the Jaeger chicks will be emerging soon. Even though I don't have more observations for this post I wanted to share some photos.

I observed a dead Red Phalarope near the nest of PAJA Pair 2. It is not uncommon for Jaegers to prey on shorebirds and passerines during the breeding season. I am not sure if it was a Jaeger kill, but I think it may have been because of the proximity of it to the nest.

Red Phalarope carcass

A mess of feathers where the phalarope must have been attacked.

I could have observed PAJA Pair 1 the other day, but there was an Arctic Fox in the area, and I did not want to unnecessarily draw attention to their nest with it around. 

Arctic Fox

I can officially confirm that one egg of PAJA Pair 2 hatched today. The other crew was doing work by it and was able to witness a chick emerging from the egg. The Parasitic Jaeger will incubate for a period ranging from 23-26 days. Incubation begins after the first egg is laid, and it can take 2.5 days for the second egg in a clutch to hatch after the first. I will be able to go over to that pair tomorrow and check it out for myself.

Jaeger hatching. Photo courtesy of Kayla Scheimreif

June 23rd 2014, PAJA Pair 2

I was finally able to spend a longer period of time observing the second pair of PAJA almost a week ago. They defended against me at 78 meters from their nest. They defended against another PAJA, a Common Raven and many Glaucous Gulls.

PAJA Pair 2             Date: 6/23/14           Time spent observing: 16:16 – 17:46

Temperature: 55 F    Wind 17 mph          50% Cloud Cover

Type of Behavior	Total Time Dark Morph	Percent time spent doing behavior	Total Time Light Morph	Percent time spent doing behavior
Defending	10	11.11	13	14.44
Incubating	60	66.67	17	18.89
Hunting/Foraging	7	7.78	2	2.22
Preening	2	2.22	35	38.9
Loafing	11	12.22	21	23.33
In flight	0	0	1	1.11
Altercation	0	0	1*	1.11

Total time spent observing: 90 minutes

* = Listed a seemingly defensive attack on a Snowy Owl as an altercation because the owl was loafing on the tundra over 200m from nest when the jaeger flew over to and harassed the owl.  

We will be pretty busy in the next week, so I will probably not have much time to observe either pair. But for now, please enjoy this video of PAJA Pair 2 defending their nest against me. It was a windy day and a lot of the "squeaks" are obscured by the sound of wind. So you may want to turn your speakers down to a reasonable level.

Questions

Since beginning these observations, and even before, I have had a lot of questions about the behavior of these birds running through my head. For now I will hash them out and later see if I can sort of narrow it to one.

1.) The first that I thought of, whether or not these birds are capable of recognizing individuals other than intraspecifically (I may have made that up). It has become clear to me PAJA Pair 1 are more defensive each year I have worked here. I think they are capable, like corvids and some terns, of recognizing individual observers, especially those that have disturbed them in some way. Thence, recognizing those individuals and behaving more, or in some cases, less aggressively.

2.) Another, and one I have loosely tested in my observations, is a question of how close to a nest can a potential predator or observer be, for the birds to begin defensive behaviors. Also, does the distance increase the closer the eggs are to hatching or the adults are brood-rearing? Additionally, do the defensive behaviors become more aggressive depending on if they have a full clutch (2 eggs) versus a single egg (as may also be the case with Pair 1's extreme aggressiveness compared to Pair 2)?

3.) In all of the literature I have read, it appears that it is more common (61% of birds measured) for males to be dark-mophs. I question if this is the case with breeding populations here with my own observations of Pair 1 over the years. As I have mentioned before, I believe the dark-morph of this pair is larger than the intermediate (as females are larger) and it was the primary attending parent when the chicks had hatched in previous years. There really is no way to test this unless I was to be on a project studying these birds by trapping and getting measurements and blood samples. But, when the eggs do hatch, it might be possible to observe the brood-rearing behavior to get a feasible idea.

4.) Just through some of my recent observations, and to coincide with the first question, what constitutes a potential threat or predator to these birds, and if they recognize those that are not worth spending their time and energy to defend against. Along with, is there a distance the potential threat has to be in proximity to the nest for the bird(s) to initiate defensive behaviors?

Again, throwing these out there mostly so I can think about them more, and how each could possibly be tested and answered.

June 21st 2014, PAJA Pair 1

I spent some more time with PAJA Pair 1 on the 21st and below is a table of the behaviors observed. The pair began defending against I and my team member at a distance of 90 meters from their nest. I was able to sit and observe them for awhile at 83 meters from the nest until about 15:33 when the dark-morph was loafing and then saw me and chased me off. I then observed them from 109 meters.

This time around the pair also defended against a Glaucous Gull which I had previously seen them ignore once. 

PAJA Pair 1               Date: 6/21/14             Time spent observing: 14:50 – 16:10

Temperature: 35 F      Wind 15 mph            100% Cloud Cover

Type of Behavior	Total Time Dark Morph	Percent time spent doing behavior	Total Time Intermediate Morph	Percent time spent doing behavior
Defending	9	11.25	2	2.5
Incubating	35	43.75	40	50
Hunting/Foraging	0	0	0	0
Preening	4	5	13	16.25
Loafing	29	36.25	24	30
In flight	1	1.25	0	0
Altercation	2*	2.5	1**	1.25

Total time spent observing: 80 minutes
* = Listed an interaction with another dark-morph PAJA as altercation, because did not clearly defend. Interaction actually appeared to be more 'friendly', since after initial interaction, they both stood on the tundra within a few meters of each other.

** = Altercation was with a pair of King Eiders, may have been harassing them if there was a nest, but I did not check if was the case.

I realize that the tables are extending beyond the bounds of the post and I am trying to fix it. I apologize if it makes it a bit more difficult to read. **EDIT: I fixed them! 

PAJA Predation Events

Since I discussed a little bit about a possible third pair and the artificial nest project, I figured I would share a few pictures the Reconyx cameras capture of the predation events.

Again, one of the projects I am working on involves setting out 60 artificial nests on a road transect that goes away from a "hub" of infrastructure. It is testing whether or not those predators considered to be subsidized by humans (Red Foxes, Glaucous Gulls, Common Ravens) are preying on nests closer to the infrastructure. The artificial nests are made with quail eggs for shorebird nests, and Mallard eggs for duck nests. We have seven Reconyx cameras that we set on artificial shorebird nests that are chosen randomly. Parasitic Jaegers are not considered to be subsidized predators, yet, it is possible that this pair has learned that the cameras provide an easy meal, and have since depredated all of our nests. Well, at least we know of three that they were caught on camera.

PAJA has spotted nest and comes in for landing.

I really like the above shot, mostly because it shows how agile and acrobatic these birds are. 

Mate comes in to investigate. Other has quail egg in bill.

Light morph takes a quail egg.

Just another nice flight/landing shot.

Two hours later, pair goes to other artificial nest. 

In this picture you can see that it has already swallowed one or more eggs, stored in the crop, and is taking another. 

I find these interesting, mostly because I have not seen that much feeding behavior in the pairs that I have been observing. It seems like they may actually forage together, or maybe in the case of one of our nests, it was near enough to their nest that they both flew over. I have read in the Birds of North America species account for PAJA, that pairs often hunt together, except when incubating. Also, when they are feeding chicks, they will often leave it unguarded to hunt together. I think it will be interesting to see if they behave this way if and when their eggs hatch.  

I have a couple of observations of both pairs that I have to post and will also write out some of my questions in the next couple of days, so stay tuned!