Pescatarians

They are back! Chester and Lacey, our Union Bay fish-loving osprey have returned from their separate winter vacations. I hope they enjoyed the easy life. I imagine they spent the winter eating sushi in the sunshine above a couple of Mexican beaches. 

On Tuesday, Lacey checked out last year's nesting platform. There have been some changes while she was gone. One minor change is the plants taking root in the nest. It looks like the nutrients left over from raising and feeding her young in 2016 have provided excellent fertilizer. 

Last year, the growth in the nest did not involve chlorophyll.

On Thursday evening, Lacey's meal was interrupted by mating. It looks like they are planning a new generation of young. Hopefully, all the changes around Union Bay do not deter them.

While they were gone, the 520 environmental remediation has killed invasive plants, planted native flora, installed irrigation pipes and created a new pond to replace the parking lot to the north of the nest.

The new plantings, along with this undisturbed grass near the Center for Urban Horticulture, have helped to provide fuel for a population explosion among the local rabbits.

In turn the rabbits have provided significant sustenance for the coyotes. The fence in the background is an attempt to protect the new, native plants from the rabbits.

The new pond has provided bathing and recreational facilities for the crows and the widespread removal of non-native plants has given the crows easier access to other bird's nests.

This crow appeared to be enjoying a robin's egg for breakfast on Tuesday. I suspect it is the intelligence of the crows which enables them to adapt and take advantage of new opportunities. In any case, the local crow population has clearly increased.

On Thursday, while Lacey was attempting to eat, the crows were constantly diving at her.

In this instance she mantled her food to protect it from the crows.

She was irritated by the non-stop harassment.

The crows stayed just out of reach. In spite of being harassed, Lacey continued to consume her fish.

After the mating, Chester started a high piercing call which ran the crows off, at least for a while. Chester has the lighter, whiter chest and Lacey has the necklace of brown - both of which help to explain their respective names and also help us to tell them apart.

This week I have been trying to prove to myself whether these two osprey truly are Chester and Lacey e.g. the same two adult osprey which nested here last year. Logically, it seems likely since the osprey would not want to build a new nest each year.

Last year by this time Chester and Lacey had gathered 'tons' of sticks and attempted to build a nest on the light poles above the baseball field. This year, I have not observed any nest building activity which implies to me they are planning to reuse their 2016 nesting platform. 

My challenge this week has been to try to isolate characteristics which would help me to identify each specific bird. My concept is that with good enough photos we should be able to identify individual birds. 

In this current year photo I can see that Lacey's dark eye stripe is thicker than Chester's and that a portion of it extends across her cheek just below the eye.

In this photo from Thursday, we can see that Chester's eyestripe is thinner and almost nonexistent under his eye.

In this 2016 photo, even looking at the opposite side of the head, it is clear that this bird looks like Chester and is obviously not Lacey.

Curiously, the patterns on top of their heads are unique as well. You may also notice that the head patterns are not symmetrical. I think these may be valuable for identification but they are much harder to observe.

Even in this more distant photo from 2016, the eye stripes provide consistent, observable identification.

I suppose one might argue that the differences we are seeing are gender related as opposed to individual characteristics.

This photo from August of 2016 shows Chester and Lacey's offspring around the time the young birds learned to fly. The eye stripes on each bird look unique to me and subtly different from their parents. I think this lends support to the idea that osprey's eye stripes can be used to identify individual birds. (One of these birds was female and the other two were male.)

In any case Spring has arrived and Lacey should begin sitting on eggs in the near future. Hopefully, we can observe the process without getting too close. The bench to the east of the platform is on slightly higher ground and provides the best views, especially with binoculars, while also giving the osprey a little breathing room. 

Have a great day on Union Bay...where osprey nest in the city!

Larry

Going Native:

Without a properly funded Environmental Protection Agency, it falls to each of us to be ever more vigilant in protecting our local environments. Native plants and trees encourage the largest diversity of lifeforms because of their long intertwined history with local, native creatures. I have been told that even the microbes in the soil are native to each local landscape. My hope is that we can inspire ourselves, our neighbors and local businesses to plant native flora and to support native wildlife at every opportunity. My intention is to include at least one photo each week and visually challenge us to know the difference between native and non-native lifeforms. 

Can you identify each of these birds and determine whether or not they are Union Bay natives?

A) 

B)

C)

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Scroll down for answers

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A) Bald Eagle

B) Common Yellowthroat 

C) Cinnamon Teal

These birds are all native to Union Bay but I do not believe any of them are year-round residents. The bald eagle is a second year bird which Chester and Lacey promptly escorted out of their territory. The other two birds are migratory birds who have just arrived for the breeding season and will be heading south in the late summer or early fall.