Merlin: An Uncommon Falcon Winters Here

In January 2019 I again spotted a Merlin in Eliza Howell Park, the fourth straight winter that I have seen at least one in this Detroit location. A Merlin is a small falcon, about the size of a Blue Jay, that feeds primarily on small birds (estimated to be 80% of its diet).

(This picture was taken recently at Belle Isle in Detroit.)

one merlin

Photo by Margaret Weber

Merlins breed in the North (mostly in Canada) and winter in the West and deep South/Central America, uncommon throughout their range. According to most range maps, like the one below from the Cornell Lab of Ornithology website, they are in southern Michigan only as migrants passing through.

20200202_172557

But some do winter here, probably more commonly now than in the past. As noted, I have seen them in Eliza Howell in each of the last four winters. But before that, I saw one in only two of the previous 10 years.

In reviewing other range maps, I did find one that recorded the Merlin’s Winter presence near Lake Erie, the map published by Audubon. Note the small blue area.

20200202_172700

Regardless of what range maps show, the Merlin is definitely (now) a Winter bird in Southeast Michigan. One should not expect to see one very often, however, given its overall low numbers. During the 2019 annual three-month-long count of migrating raptors at the Detroit River Hawk Watch, there were only 34 Merlins counted. Compare this number with 64,336 Broad-winged Hawks (the most common) and with 62 Golden Eagles, another uncommon bird in this part of the country.

A Merlin often perches in a tree near an open or brushy area, looking for small birds on or near the ground. I tend to check the scattered leafless trees during every Winter visit, looking for the silhouette. When I spot one, I try to walk close enough to identify and to watch. They are not spooked as easily as many other raptors, so one can sometimes get quite close before they fly away.

20200203_123947

Falcons are very fast flyers and a Merlin uses its speed to catch small birds in flight. On one of my first experiences of a Merlin in Eliza Howell, I watched as one flew into the woods with a bird in its talons, perched in a tree by the river, and spent the next half hour removing the feathers (which floated down to the river) and consuming its catch.

They are usually solitary, but on the recent Belle Isle occasion, we came upon a pair.

two merlins

Photo by Margaret Weber

Merlin the bird is perhaps not as well-known as Merlin the wizard (in Arthurian legend). This is understandable, as it is not numerous anywhere and not typically a resident of the eastern half of the United States. But it is out hunting from a perch on Winter days in Southeast Michigan and it is great to occasionally have the opportunity to observe.

Gray Catbird: Predictable Departure Time

My October bird watching in Eliza Howell Park in Detroit is largely focused on birds Coming, birds Going, and birds Passing Through. “Coming” are those species that breed in the far North and spend their winters here; “Going” birds breed here and head south for the winter; “Passing Through” birds breed north of southern Michigan and winter to the south of us.

Very early October is the time to expect my last sighting of the year of one of my favorite park summer residents: the Gray Catbird.

catbird rufus showing

Photo by Margaret Weber

According to my records, the Catbird is typically here at the end of September but gone by the end of the first week of October. At this time of the year, I often walk through the wildflower field along the edge of the woods checking to see what birds have shown up overnight. The view is slowly transitioning to a Fall look.

20190925_080635

Birds like this area because it is a good place to forage for food, whether that food be insects or seeds (most of the wild flowers are now in seed) or berries from the many vines and shrubs at the edge. For most of the summer Catbirds eat insects, but when fruit is available as it is now, they eat a variety of berries.

catbird wt berry

Photo by Margaret Weber

They are called “catbirds” because their wailing reminds people of a cat meowing. They are mimics, however, and especially when singing earlier in the season, can produce a great variety of sounds.

They spend the winter near the cost in the southeast U.S. or Mexico or in the Caribbean or Central America. (The Range Map is from the Cornell Lab of Ornithology.)

20190930_200719

Their spring arrival date is also predictable. I usually first spot one in the park between April 30 and May 4. Shortly thereafter they begin to seek out a nesting location; they place their nests in thickets, several feet off the ground. It often takes careful thicket searching, but I have had some success in finding their nests. Their eggs are a striking color (turquoise green?).

20190601_115347

Several pairs spend the summer in Eliza Howell Park. At least one Catbird was still present yesterday, October 1. It might have been the last day I see one in 2019, 5 full months after the first appearance in the spring.

Thank you for spending the time with us.

20191001_131426

Photo by Margaret Weber

One of the joys of nature watching for me is the predictability of the annual sequence of events. And very few events are more predicable than the time of  the annual departure from Eliza Howell of the Gray Catbird.

September 7 Nature Walk

The second of the annual Detroit Audubon field trips to Eliza Howell Park takes place on Saturday, September 7, 2019, starting at 8:00 a.m. The public is invited; there is no cost.

Timed to coincide with the early days of the Fall bird migration, this walk give special attention to birds, especially warblers headed from the North Woods to Central and South America. Depending upon the weather conditions, we are likely to see several warbler species, perhaps including these three. (Thank you to Margaret Weber for these three photos.)

Black_&_White_Warbler_1

Black and White Warbler

nashville_warbler

Nashville Warbler

Am Redstart 2018

American Redstart

The fall warbler migration begins at the end of August and continues into October, with individuals of some 20 different species making short stops at Eliza Howell. The find from one day to the next is almost always different.

If September 7 is a good day, the birds will keep us quite busy, but we will also stop for non-bird observations. This is about the best time of the year to note the variety and nature of spider webs among the wildflowers and the shrubs. They vary in sizes and shape; this is a small one on a thistle.

20190821_164304

September is also the month when I most frequently see a Praying Mantis (or 2 or 3). They have reached maturity and may be seeking mates and/or laying eggs. (I wrote about “Praying Mantis Egg Laying” on September 13, 2018.)

20180907_141645

Butterflies continue to be present. One of my favorite late-season butterflies is the Common Buckeye, which makes it appearance in Eliza Howell after the July butterfly peak.

20180911_135735

I usually find several Bald-faced Hornet nests in the park each year, beginning about this time. We may want to stop for a look (through lenses) to watch the hornets enter and exit the hole near the bottom of these amazing constructions. (For more, see “Bald-faced Hornet Nests,” December 12, 2017.)

20170831_110321

Blue Jays migrate in September and many spend days at Eliza Howell harvesting acorns, from the middle of September into October. (For more information, see “Blue Jays Harvesting Acorns,” August 27, 2018).

September 7 might be a little early to see them at work, but we will check (this photo also courtesy of Margaret Weber).

20181011_144616

The seasons repeat themselves, so it is possible to predict what might be seen at any given time of the year. But it is also true that every day is different and almost every walk includes an element of the unexpected. Such is the nature of nature walks. September 7 should be fun.

Blue-gray Gnatcatcher Nest: The Rest of the Story

On May 28 this year, I wrote about finding an easily visible Blue-gray Gnatcatcher nest in Eliza Howell Park and concluded my comments this way:

“One of my goals each year for the June Detroit Audubon-sponsored field trip to Eliza Howell Park is to be able to point out an active Blue-gray Gnatcatcher nest, even if I cannot expect others to be quite as enthusiastic as I am about this tiny bird and its fascinating nest.”

20190527_142953

The field trip took place on June 8, which, according to my estimate based on observed behavior, was about day 10 of incubation (of a normal 11 – 15 day incubation period). When the our whole group stopped to look, the bird remained on the nest, watching us but not threatened enough by our presence to leave. Melissa Francese took this picture at that time.

20190620_162556

A few days later the eggs hatched. By June 18, when Kevin Murphy took the next two photos, the young were nearing the end of their in-nest development.

20190620_163940

It is difficult to tell because they were constantly moving, but my various efforts to count heads led me to conclude that there were probably 4 nestlings. While the female does most of the incubating, both female and male feed the young.

20190620_163920

They are now gone from the nest, successfully fledged as far as I can tell. While Blue-gray Gnatcatchers occasionally brood twice in a year, my nest watching of this species is likely over for the year.

They are nearly halfway through their stay of 4 + months in Detroit (arrive in late April and depart in September), spending the majority of their year far to the south. (Range map from Cornel Lab of Ornithology).

20190620_171200

I will continue to see them foraging in the park for a couple months (photo by Margaret Weber).

20190620_165114

And each time I see one, I will feel a sense of appreciation for weeks of enjoyable nest watching this year and for a highlight of the 2019 June Audubon field trip.

The Red Wings Are Coming

It was on “the eighteenth of April, in seventy five” (in Longfellow’s poem) that “the midnight ride of Paul Revere” occurred, when he spread the alarm that the Redcoats are coming.

As the first of March approaches every year, it is time to announce, with eager anticipation instead of alarm, that the Red Wings are coming to Eliza Howell Park (the Red-winged Blackbirds, that is, not the Detroit professional hockey team).

Usually the first of the summer residents to return for the breeding season, Red-winged Blackbirds often arrive when winter is still very much present. Twice in the last 10 years I have seen the first of them on February 27.

The males seem to be in a particular hurry to claim a breeding territory.

20190222_192050

       Note: The bird photos here are all by Margaret Weber.

As I enumerated in a posting last year (“The March 10 (or 11),” February 22, 2018), the bird population in the park begins to grow rapidly in March. Among these early arrivals, the Red-winged Blackbird is usually the first and often the most easily visible.

The males arrive before the females, who might not make it till late March. These females will find the males, with their bright red patches and singing loudly, ready to welcome them to the territories they have claimed.

20181231_134725

Females look very different. In fact, it can take some experience to identify them as the same species; they resemble sparrows in some ways.

20190224_205345

As can be seen from the range map, most RWBs winter in the states and some do not have far to travel to reach Detroit before spring does. (The map is taken from the Cornell Lab of Ornithology.)

20190222_135048

In Eliza Howell Park, there are several nesting “pairs” each year. I put “pairs” in quotation marks because this is a species that does not breed as a simple one-male one-female pair. The male often mates with and protects several females in his territory and genetic studies have shown that quite frequently the nestlings are not all sired by the territorial male.

In marshes, Red-winged Blackbirds often nest in cattails. Outside of the marshes, and in Eliza Howell Park, they nest in tall grasses or in shrubs and small trees. The nests are open on top and often have 4 eggs. I found this nest in May a couple years ago.

20160520_132448

The picture is not very clear because I didn’t linger long enough to get a good shot. Red-winged blackbirds are very aggressive in protecting their territory and their nests. They chase much larger birds and animals of all sizes, including humans. It is advisable to have head protection of some sort when walking near nesting Red-winged Blackbirds. It is common to experience “dive bombing” that seems to be aimed directly at the head.

They come flying, not just to impress females, but also to protect against intruders.

20190222_191837

The Red Wings are coming. The spring birding season is beginning.

 

 

 

The Strange Case of Blue Jay Migration

Blue Jays have been a major presence in Eliza Howell Park during the last month, the time of their fall migration. Each year I anticipate their acorn harvesting frenzy (see “Blue Jays Harvesting Acorns,” August 27, 2018) and this year they again worked the oak trees in great numbers.

Note: All bird photos by Margaret Weber

20181011_144616

Their month-long period of intense activity in Detroit is exciting to observe, but I am increasingly aware of their unusual – and not fully understood – migration behavior.

Most birds that migrate through our area in the fall leave all or much of their breeding ground for the winter. Blue Jays, by contrast, are found in the very same areas all year round. It is interesting to compare the following two range maps. The first is White-throated Sparrow, also moving through here in September, and the second is Blue Jay. (These maps are taken from the Cornell Laboratory of Ornithology website.)

White-throated Sparrow range

20181012_090114

White-throated Sparrows leave almost their entire breeding area in the fall.

Blue Jay range

20181010_134337

Blue Jays are found throughout winter in the very same areas in which they breed. A few scatter to the west, but the entire breeding area remains occupied.

Such a range map usually suggests that a species is non-migratory. Blue Jays, however, migrate and do so in great numbers. Every fall the raptor counters at the two locations by Lake Erie (Detroit River Hawk Watch at Lake Erie MetroPark and Holiday Beach Conservation Area in Amherstburg, Ontario) count Blue Jays as well as raptors. As of October 10 this year, Holiday Beach watchers had reported over 350,000 Blue Jays moving through since early September. And the migration wasn’t fully over yet.

20180824_131530

This is what is known (and/or thought likely) about Blue Jay migration, based on my review of some of the published research:

  • The species is partially migratory; only some migrate
  • Most that migrate go only a few hundred miles south in the fall
  • It is estimated that fewer than half migrate
  • Those that migrate (and those that don’t) include both young birds and older birds
  • Individual birds might migrate one year and not the next and then migrate again in the following year
  • The migration number in a particular year is suspected to be related to food sources

The jay numbers will soon decline in Eliza Howell as the migrants move on. But I do not know whether individual birds like this one, seen in an oak tree in September, will stay for the winter.

20181011_144733

I do not know whether this one, nesting here in June, will be around in the coming winter

Resized_20180508_171302

I had assumed, if I thought about it much at all in the past, that the same birds (the non-migrants) were present in summer and winter and the migrants all passed through. Now I doubt that.

One of my other questions, not addressed in the limited research I have reviewed, is whether some of the individual jays harvesting acorns in the park leave/migrate before the winter and do not ever go back to eat the acorns they hid. Is acorn harvesting possibly community and not just individual food-gathering?

The Blue Jay is a common bird, so it is tempting not to give it a second thought. But I rarely see jays these days without thinking about what I do not know about them.

An October Morning Walk: Today’s News

I arrived in Eliza Howell Park on October 9, 2018, at about 8:20 a.m. It was already warm, very warm for this time of the year, after a heavy dew. For the next three hours I walked about with my binoculars and phone camera, with frequent stops.

These are some of my observations on what is happening in the park today.

1.Sun and Dew

When the morning sun shines, it highlights the wet twigs and leaves, and the moisture rises in the air like fog. The temperature was unusual for October, but the picture is not.

20181009_152829

2.Honeysuckle berries getting ripe.

There are many honeysuckle shrubs (Amur honeysuckle) in the park. They have lovely white flowers in the spring, but are perhaps even more attention-getting in the Fall. They keep their leaves longer than most deciduous plants and will be mostly green with abundant red berries into November. They have been ripening slowly and more are red every day.

20181009_085605

3.Mushrooms continue in season.

I recently posted a report on some of the mushrooms in the park (October 4, 2018). Mushroom season continues and, in the last few days, there are even more to be found, in many shapes and sizes. This is just one of many I thought photo-worthy today.

20181009_155735

4.Migrating sparrows arriving.

As I noted in another post (September 28, 2018), part of my October focus is on the variety of sparrows that pass through the park. This morning I saw six different sparrow species, including a flock of Dark-eyed Juncos and my first-of-the-season Field Sparrow (pictured here in a photo from another time).

20180921_133215-1

Photo by Margaret Weber

5.Monarch butterflies are still present.

Monarchs have been in migration to Mexico for about a month now and I have been checking for them during each visit to the park to see whether there are any still present. Today I saw 4. So they have not yet all passed through, though that will happen soon.

I thought today of the Monarch caterpillar that I saw on September 12 (picture) and wondered then whether it would have time to make it to butterfly in time to head to Mexico with the others. Perhaps it is now on its way.

20181009_160810

6.Chestnuts are falling.

Many, maybe most, of the nuts and acorns in Eliza Howell have already fallen. When mature chestnuts fall, the outside shell (the burr) opens on its own – to the benefit of squirrels and others. Many empty burrs are now on the ground under the trees. Sometimes the burrs open before they fall; this one is still on the tree, with two of the three nuts having dropped. (For more about EHP chestnuts, see post of July 31, 2018.)

20181009_101218

7.Tree leaves are starting to turn.

Except for the species whose leaves turn red early (such as staghorn sumac and Virginia creeper), most of the leaves in the park are still green in early October. Today, however, there are definite signs that the change has begun on some of the large deciduous trees.

20181009_153922

8.Second hornet nest found.

Bald-faced hornets often build nests in a number of trees scattered around the park. I typically see 10 or more each year, starting to spot them in late summer but finding most in the fall when they become more visible with the leaves thinning or gone. This year I had only seen one so far, a small one, found on August 17 and pictured here, and have begun to wonder whether this year might be atypical. Today I (finally) found a second one.

20180817_111236

9.Purple love grass starting to tumble.

Anyone visiting the park in late summer or early fall is likely to notice the hue of the foot-high plants called purple love grass. When the grasses dry up, they (now brown) detach and blow across the ground like tumbleweed. Tumbling is now starting to happen. (The picture is from mid-September.)

20180912_170506

10.Snails feeding on stems.

The terrestrial snails common in Eliza Howell (perhaps a type of banded snail) have been active since April, when they emerged from hibernation. They seem to be especially abundant right now, climbing up several feet on plant stems (they feed on both live and dead plants). Here is a collage of four I saw today.

20181009_155048

These are some of my notes from a morning walk in the park.

 

Four Months Here, then Gone Again

Among the birds that breed in Eliza Howell Park and “winter” in or near Central America, I selected four and reviewed my records on first sighting and last sighting in the park each year from 2010 to 2018 (9 years). The dates indicate clearly that they are only short-term residents here, coming to breed, and longer-term residents elsewhere.

Note: All photos by Margaret Weber

Baltimore Oriole

20180520_145512

I do not get to the park every day and, of course, I miss some birds when I am present. Nevertheless, the record is quite consistent. Based on this experience, I expect to see the first Baltimore Orioles of the year the first week of May and will probably not see them after the first week of September.

Baltimore Oriole 2010 – 2018

First seen:     5/6    5/8   5/2   5/5   5/6   5/6   5/7    5/1    5/4

Last seen:     9/3   8/25  9/5  8/22  9/7   9/7  9/11   9/4   9/3

By the end of May, I start finding Baltimore Oriole nests every year in the large trees, often near the road, and find a total of five in a typical year.

Barn Swallow  

Resized_barn_swallow-1

Barn Swallows also nest in the park every year, at least one pair under a shelter and several under the Fenkell Avenue bridge over the Rouge River.

Barn Swallow   2010 – 2018

Fist seen:   4/24  4/23  4/19  5/1   4/17   4/26   4/22  4/29  4/25

Last seen:   9/2  8/28   8/24  8/22  8/24  8/23  8/20    9/9   8/31

Blue-gray Gnatcatcher

20181002_213231

The Blue-gray Gnatcatcher arrival date (more exact, first sighting date) is spread over a three week period, not as consistent as with the Baltimore Oriole. The last-sighting date covers a shorter range of time. By the end of the second week of September, they have started their trip back to Central America (some to Florida) for a longer stay.

A couple pairs of gnatcatchers always nest in Eliza Howell and I have been successful most years in locating a nest to point out to participants in the June Detroit Audubon breeding bird field trip.

Blue-gray Gnatcatcher 2010 – 2018

First seen: 5/3  4/28  4/19  5/1  4/23  4/11  5/1  4/20  4/28

Last seen:  9/6  9/14   9/9   9/2   9/7   9/7   9/11   9/4   9/5

Ruby-throated Hummingbird

male ruby throated protrait

There are always a small number of Ruby-throated Hummingbirds that spend four month at Eliza Howell, but I have found an actual nest only once over these years. I am quite sure they nest here every year, however, based on the behavior of adults and on the slight increase in numbers by late summer. They spend the non-breeding months in Central America.

Ruby-throated Hummingbird 2010 – 2018

First seen: 5/12  5/8   5/10  5/14  5/10   5/15  5/13  5/11  5/4

Last seen:  9/6   9/5    9/9    9/14  9/14  9/13   9/16   9/9   9/22

—-

These four species are not the only birds that nest in the park and leave after breeding season, but these records may be sufficient for now.

—-

There are several points to be made based on the above records.

  1. Birds that migrate are amazingly consistent from year to year. It is often possible to predict when (within a week or so) a particular species will show up again.
  2. If someone wants to see any of these four species in October, don’t come to Eliza Howell.
  3. This information, along with the annual fly-through of the warblers, helps to explain why many bird watchers in this part of the country go a little crazy as May approaches. By then, it will have been a long time that some favorites have been gone.

October Sparrow Expectations

Each year I look for 10 different sparrow species during the month of October in Eliza Howell Park. In the last six years, I have twice seen all 10 and twice seen 9 of the 10.

——

Note 1: Detroit Audubon is sponsoring a Field Trip at Eliza Howell on October 20, 2018, at 9:00 a.m. Sparrows are among the target birds, as are migrants like Golden-crowed Kinglet and Purple Finch. Non-Audubon members are welcome.

——

Note 2: All bird photos in this essay were taken by Margaret Weber.

——

White-crowned Sparrow

20180921_133336

The 10 October sparrows fall into three categories: 1) those that migrate through in the spring and again in the fall; 2) those that are summer residents and are about to leave for the south; and 3) those that are just arriving to spend the winter in Detroit.

Six of the 10 are in the migrant category. White-crowned Sparrow is one. It breeds in north Canada, where it is common, and winters in parts south of Michigan.

Field Sparrow

20180921_133215

Southeast Michigan is part of the breeding range of the Field Sparrow, but I typically see it in Eliza Howell only in the spring and the fall. Thus, I count it as a migrant in relationship to the park. It is a regular brief visitor in October.

White-throated Sparrow

20180921_132554

The White-Throated Sparrow is another migrant regularly seen in late September and in October. It breeds in northern Michigan and Canada and winters just to the south. In fact, we are at the northern edge of the winter range and they are sometimes seen in SE Michigan in winter.

Three other migrants that usually show up in October in EHP are not pictured here: Lincoln’s Sparrow, Fox Sparrow, and Swamp Sparrow.

Chipping Sparrow

20180921_132910

The Chipping Sparrow is one of two summer resident sparrows that are normally still seen in October. It always arrives in April and heads for the deep south states for winter before the end of October.

Song Sparrow

20180116_085155

The Song Sparrow, the other summer resident on this list, is the most common EHP summer sparrow and the closest to a year-round resident among the sparrows. Some years, one or two individuals stay through the winter.

American Tree Sparrow

20180921_132813

The A. Tree Sparrow is a winter visitor and the one of the 10 that is least reliably seen in October – simply because it sometimes doesn’t arrive until November.

It is a true northern breeder, as can be seen from the range map, taken from the Cornel Lab of Ornithology.

American Tree Sparrow range map

20180925_124219

Dark-eyed Junco

20180921_133821

The other winter resident is always found in October in EHP, the Dark-eyed Junco. Though “sparrow” is not a part of its name, that is what it is. It usually arrives early in October and stays until April. Known as the “snowbird,” its arrival signifies to many that winter is coming.

—–

There are two other sparrows (Savannah Sparrow and Vesper Sparrow) that I am likely to see in the park each year, but not on a predicable basis and not in October. Next week is October and I am ready with my sparrow expectations.

 

Blue Jays Harvesting Acorns: Coming Soon

It is almost September and the acorns are nearing maturity. A fascinating Eliza Howell bird-watching occasion will begin soon.

Blue Jays in southern Michigan in September are both migrants and year-round residents. Blue Jay migration is different from that of most other birds. They are found throughout their general range in both summer and winter, but large numbers move from one location to another in spring and fall. Mid-September to early October is the time of the largest numbers in the park, many more than in the rest of the year.

Eliza Howell has a number of large oak trees within the road loop and the acorn crop is the main attraction for the jays.

20180824_131359

Photo by Margaret Weber

Last year (2017), I did more careful observation than previously. It began with noticing that many of the acorns that I was crunching as I walked under one of the pin oak trees were really just the caps; there were far fewer nuts on the ground. I thought that the jays were probably responsible for removing the caps but I had never really given careful attention to their harvesting behavior, beyond observing their preference for oak and beech trees.

I decided to watch. In the late morning of September 22, I sat in the shade of another oak tree and watched the pin oak the Blue Jays were frequenting.

20180825_173324

My observations:

  • The number of jays coming and going was considerably greater than I had expected. Those flying out almost always often had an acorn in the beak.
  • Individuals in the tree moved quickly from one small branch to another, efficiently securing acorns (with only a few being dropped or knocked to the ground).
  • After picking an acorn, the jays flitted to a larger limb, where they held the acorn with the feet and pecked or hammered at it.
  • While in some cases they might have been breaking the acorn open and eating it, the hammering was most often to remove the cap, which fell to the ground.
  • The jays then appeared to swallow the nut whole and move on to get another.
  • I knew that jays do not eat acorns whole, so I wondered exactly what was going on. More watching revealed a bulging throat pouch in some of the jays.

20180824_131445

Photo by Margaret Weber

I knew, of course, that Blue Jays carried off acorns to store for future use, but I assumed they carried only one at a time, in the beak. Reviewing some published reports on the acorn storing behavior of jays, I found that they typically carry several acorns at a time to cache. They hold acorns in their “gular pouch” (usually 2 – 3, sometimes more), may carry another in the mouth, and have in the beak as well. They take them to the caching location (which may be a half mile away or more), regurgitate them, and hide each individually on the ground.

The next day I went back for further observation of the jays in the same pin oak tree. From a stationary position where I could see the entire tree from top to bottom, but where I could not observe the “back side,” I watched the Blue Jays coming and going to the tree for a 30 minute period on a sunny morning, from 9:56 a.m. to 10: 26 a.m.

  • I recorded jays flying into the tree 94 times and flying out 98 times.
  • I estimate that there were 7 or more birds in the tree at any given time.
  • I have no way of knowing how many individual jays returned how many times, so cannot estimate of the total number of individuals harvesting pin oak acorns from that one tree.
  • If I assume that the average trip out included at least 2 – 3 acorns, and recognize that this was just a 30-minute segment of one day (the jays have been “working” the tree for a number of days and for hours each day), it is likely that the number of acorns harvested by Blue Jays from this one tree this one year may be 8,000 or more.

20180824_131506

Photo by Margaret Weber

I now have additional questions. Based on what I observed, I now wonder whether I can continue to assume that most of the Blue Jays present in the park every September are migrating through. As I watch the jays in the tree, there was clearly much more “pouching” of the acorns than eating on the spot. Do migrating Blue Jays that are not going to be in the area for more than a short period of time harvest acorns and cache them? Maybe a number of year-round jays from neighborhoods outside the park come to the park in September for the acorn harvest?

20180825_173430

The acorns in August remind me of what is coming and I am looking forward to September watching. Perhaps I will learn a little more about these common birds this year. Perhaps I will have additional questions.