Angry Swan

 By Richard B. Primack

“It is true, nothing could originally demand our respect, which was not, at the same time, capable, in a greater or less degree, of exciting our fear, but this does not prove fear to be the source of that respect.” Henry David Thoreau in his Early Essays and Miscellanies.

My son Dan and I had a remarkable encounter with an extremely angry and protective swan while kayaking on the Charles River two weeks ago. As we rounded a bend in the river in Dedham, we observed a family of swans, consisting of two adults and three babies. We kept to the opposite bank of the river to keep as far from them as possible. Despite this, the bigger adult swan, presumably the male, swam aggressively towards us with its wings raised up.

Photo 1: Angry swan with wings raised. Optic Mag

For about 10 minutes, the angry swan kept trying to get very close to us from behind, presumably to peck us and scare us off. We faced our kayaks toward the swan, and also used our paddles to keep it at a distance of six feet away. The swan continued this aggressive behavior even as the current took us 50 yards from the babies. There was a slightly humorous quality to the encounter, but it was also surprisingly tense as the swam seemed intent on doing us harm. 

Photo 2: Angry swan flying to attack. RealMantis

Finally, the swan flew back to its family, and we laughed out loud in relief, thinking that the strange incident was finished. But a few minutes later, the swan flew back to us, even though we were now more than 100 yards away from the family and paddling in the opposite direction. The swan proceeded to confront us for another five minutes, again trying to get behind us. We were relieved when the swan finally flew back to its family. 

We did not take any photos or videos of this swan, as we were so concerned about our safety during the episode. But here are videos of other swan encounters:

Video 1

Video 2

Video 3

Korean Flowering Data Show Dramatic Impact of Climate Change

 By Richard B. Primack

“I think that we may detect that some sort of preparation and faint expectation preceded every discovery we have made.”Henry David Thoreau in his Journal.

Since 1921, the Korean Meteorological Agency has been recording the flowering times of trees and shrubs in experimental gardens located at 74 weather stations across the country. This century-long record of plant activity, unequalled in all of Asia, has provided important fuel for climate change research. 

Figure 1: Sites of weather stations in South Korea.

Figure 2: Researchers at the Seoul weather station posing in front of flowering forsythia shrubs. Co-author Sangdon Lee is in the middle.

In a recently published article, we report that plants at these weather stations, including cherry trees and forsythia, are responding to record high temperatures with unprecedented earlier flowering times. There is no evidence that this advance toward ever earlier springs is stopping, as record high temperatures continue. In addition, these changes were surprisingly consistent and predictable given the magnitude and pace of change. 

Figure 3: For seven woody species, plants flower earlier in the spring in a consistent manner with warming spring temperatures. 

Why do these results matter? They show that the timing of spring is earlier now than at any point in the past 100 years. This will impact a range of natural processes and segments of society and the economy, such as agriculture and tourism, that depend on the timing of spring. It’s important to note that the changes in timing might be predictable, at least in the short term, providing an opportunity for people to anticipate and prepare for them.

Figure 4: Co-authors Sangdon Lee and Richard Primack discussing the project under a flowering cherry tree at one of the weather stations. 

As the planet continues to warm, the Korean data and this study can play a crucial role in identifying limits to nature’s response to climate change which can help guide us in minimizing the harmful impacts.

Figure 5: Planting of woody plants for monitoring at one of the weather stations.

The research team published this work in New Phytologist:   

Consistent, linear phenological shifts across a century of observations in South Korea by authors William Pearse, Michael Stemkovski, Benjamin Lee, Richard Primack, and Sangdon Lee.

Here is a link to the article: LINK

Generating Ecological Insights from Historical Data

 By Richard B. Primack

 

“The past is the canvas on which our idea is painted - the dim prospectus of our future field. We are dreaming of what we are to do.” Henry David Thoreau in his Reform Papers.

Ecologists worldwide are searching for historical datasets that can provide insights into how ecosystems and species are responding to climate change, often with a focus on changes in species’ phenology, distribution, and abundance.

In a recent article, we describe a number of examples of this approach, including a resurvey of Joseph Grinnell’s records of birds in the California mountains and our own research repeating Henry David Thoreau’s observations of the plants and birds in Concord, Massachusetts.  

Figure (a). Statue of Thoreau with a replica of his cabin at Walden Pond State Park. 

 

The digitization of museum collections and the recent explosion in citizen-science projects, such as Nature's Notebook and eBird, are offering new sources of data to test possible links among ecological phenomena, both past and present, observed at various scales.

Figure (b). Locations of herbarium specimens used to determine if Concord phenological patterns occur across eastern North America.

Figure (c). Herbarium specimen of trout lily (Erythronium americanum), a woodland wildflower. 

These types of studies – linking detailed site-specific historical datasets with larger-scale data from museum collections or citizen-science records – provide two additional benefits: they can help assess the quality of local-scale datasets and they can create compelling stories to communicate to the public about science in general and climate change in particular.

Figure (d). Based on herbarium specimens, the window of spring sunlight available to woodland wildflowers is predicted to decrease by 2100, with the strongest effects seen in the north.

Access the article here: LINK  

Herbarium Specimens Predict Flowering Times of Grasses that Contribute to Pollen Allergies

 By Richard B. Primack

 

“The old naturalists were so sensitive and sympathetic to nature that they could be surprised by the ordinary events of life.” Henry David Thoreau in his Journal.

 

The grass family is responsible for many pollen allergies, which are predicted to increase with global climate change. Unfortunately, since standard airborne pollen monitoring techniques don’t provide species-specific pollen identification, these methods end up grouping all grass species together which undermines their usefulness.

Figure 1.  Locations of airborne pollen monitoring stations in Denmark.

 

As reported in a recent article, we obtained flowering data for 12 allergenic grass species using thousands of herbarium specimens collected across Denmark over 190 years. We then compared these data to pollen monitoring data. 

Figure 2.  Herbarium specimen of velvet grass (Holcus lanatus) collected in Denmark on July 1, 1870.

Seven of the grass species included in the data are major contributors to airborne pollen based on their relative abundance in the wild and the overlap of their flowering times, determined based on herbarium collections, with when maximum airborne pollen loads are detected. In addition, many grass species are also flowering earlier in response to warmer spring temperatures.

Figure 3. Velvet grass herbarium specimens with flowers have the same seasonal distribution as the pollen density at airborne monitoring stations. (DOY=Day of Year) 

Figure 4.  Creeping velvet grass (Holcus mollis) herbarium specimens with flowers do not have the same distribution as the pollen density at airborne monitoring stations. (DOY=Day of Year)  

This type of data derived from natural history collections can contribute to the advancement of pollen forecasting for asthma and allergy patients both under current conditions and in the coming decades as climate change continues.

 

Access the article here: LINK

At Famed Walden Pond, Spring Is Coming Earlier Than In Thoreau’s Day

 By Richard B. Primack

 

“I would rather save one of these hawks than have a hundred hens and chickens. It is worth more to see them soar.” -- Henry David Thoreau in his Journal.

 

The detailed record of bird sightings and phenological observations around Concord, Massachusetts—from Thoreau’s notes 170 years ago to today’s studies by local bird enthusiasts and our research group—provides a key to studying how climate change is affecting bird migration.

 

Figure 1.  Yellow warbler collecting a caterpillar. Sam Zhang/Macaulay Library

The most important finding yielded thus far is that birds are not arriving earlier now than they did in the past. It appears that birds are not nearly as responsive to a warming climate as are trees, wildflowers, and insects. This could potentially lead to a phenological mismatch, and negatively impact the populations of migratory birds that miss the first early pulse of insect emergence. 

 

Figure 2.  Plants are showing a strong pattern of earlier leafing out and flowering in the spring. The response of birds is not as strong or consistent. 

This work is presented in the Spring 2023 issue of Living Bird (April 5, 2023): LINK